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  1. Tachs
  2. Recognize punctuation and capitalization errors (as tested)

TACHS WRITTEN EXPRESSION • STANDARD ENGLISH: IDENTIFYING ERRORS

Recognize punctuation and capitalization errors (as tested)

Learn to spot missing commas, wrong end marks, and capitalization mistakes so you can ace error-identification questions.

SECTION 1

Why Punctuation and Capitalization Rules Exist

Have you ever read a text message with no periods or capital letters? It can be really confusing! Punctuation (marks like periods, commas, and question marks) and capitalization (using uppercase letters in the right places) are tools that help readers understand writing clearly. These rules did not appear overnight. They developed over hundreds of years.

200 BCE
Early Dots in Greek Writing
Ancient Greek librarians in Alexandria placed dots at different heights to show readers where to pause. This was one of the first punctuation systems ever used.
800 CE
Capital Letters Emerge
Monks copying books by hand began using larger letters at the start of sentences. This helped readers see where new ideas began.
1450s
The Printing Press Standardizes Rules
When Gutenberg invented the printing press, printers needed consistent rules. Commas, periods, and capital letters became standard across printed books.
1900s–Today
Modern Grammar Guides and Tests
Schools and tests like the TACHS now expect students to know punctuation and capitalization rules. These rules help you communicate clearly in school, at work, and online.

On the TACHS, you will see sentences that may contain errors. Your job is to find the error—or decide that there is no error. Let's learn the rules that will help you do that.

SECTION 2

Core Rules You Need to Know

There are a handful of key rules that show up again and again on the TACHS. If you learn these rules well, you will be ready for most error-identification questions. Let's look at the big five.

1

End Marks

Every sentence needs a period (.), question mark (?), or exclamation point (!) at the end. Match the mark to the sentence type.
2

Commas in a Series

When you list three or more items, put a comma after each item except the last one. Example: "I packed shoes, socks, and a jacket."
3

Commas After Introductory Words

When a sentence starts with a word or phrase like "However," "First," or "After the game," place a comma before the main part of the sentence.
4

Capitalize Proper Nouns

Names of specific people, places, months, days, holidays, and titles always begin with a capital letter. Common nouns (like "city" or "dog") stay lowercase.
5

Apostrophes

Use an apostrophe to show possession ("Maria's book") or to form a contraction ("don't" = do not). Don't confuse "its" (possessive) with "it's" (it is).
✦ KEY TAKEAWAY
Think of punctuation marks like traffic signs on a road. A period is a stop sign. A comma is a yield sign that tells you to slow down briefly. A capital letter is like a big green road sign telling you the name of a place. Without these signs, drivers (or readers) get lost!
SECTION 3

Seeing Errors in a Sentence

The diagram below shows a sample TACHS-style sentence broken into parts. Each part is checked for punctuation and capitalization. Look at how the error is highlighted in red and the correct version is shown in green.

Anatomy of an Error-Identification Question"last saturday, my family visited the bronx zoo and we saw lions tigers and bears."ERROR 1"last saturday" → missing capitals✓ "Last Saturday"Days and months are proper nouns.ERROR 2"lions tigers and bears" → missing commas✓ "lions, tigers, and bears"Commas separate items in a series.Corrected Sentence"Last Saturday, my family visited the Bronx Zoo, and we saw lions, tigers, and bears."= Error found= Correct version
This diagram shows two common errors in one sentence: a capitalization error ("last saturday" should be "Last Saturday") and a punctuation error (missing commas in a list). The corrected version appears in the green box at the bottom.

Notice that the word "Bronx" also needed a capital letter because it is the name of a specific place. On the TACHS, you might see only one error per question. Read every word carefully and check each part of the sentence against the rules you have learned.

SECTION 4

How the TACHS Tests These Skills

On the TACHS, error-identification questions usually give you a sentence divided into underlined parts. You pick the part that has an error—or you choose "No error" if the sentence is correct. Let's break down the strategy you should follow.

The 4-Step Error Check

  1. Step 1 — Read the whole sentence. Get the overall meaning first. Don't jump to the underlined parts right away.
  2. Step 2 — Check capitalization. Look for proper nouns that are lowercase or common nouns that are incorrectly capitalized.
  3. Step 3 — Check punctuation. Look at commas, periods, question marks, exclamation points, and apostrophes. Is anything missing or used in the wrong place?
  4. Step 4 — Choose your answer. If you find an error, pick that underlined section. If everything looks correct, choose "No error."
💡 Test Tip
About 20% of TACHS error-identification questions have no error. Don't force yourself to find a mistake when there isn't one. Trust your knowledge of the rules!

Common Capitalization Traps

Capitalization Rules Quick Reference
CapitalizeDo NOT Capitalize
Names: Maria, Dr. LeeGeneral titles: the doctor, a teacher
Specific places: Bronx Zoo, Lake MichiganGeneral places: the zoo, the lake
Days, months, holidays: Monday, July, EasterSeasons: summer, winter, fall
Languages and nationalities: Spanish, FrenchSchool subjects (general): math, science
Titles of books and movies: The Lion KingShort words in titles (unless first): of, the, and
SECTION 5

Punctuation Rules in Detail

Punctuation errors are the most common mistakes tested on the TACHS. The diagram below groups the main punctuation rules you need to know and gives you a quick example for each one.

Punctuation Rules MapPUNCTUATIONEND MARKSCOMMASAPOSTROPHESPeriod (.)Statements: "She ran fast."Question Mark (?)Questions: "Did she run?"In a Series"red, white, and blue"After Introductory Words"First, open the book."Before Conjunctions"I ran, and she walked."Possession"the dog's bone"Contractions"can't" = cannotWatch Out!its ≠ it'sQuick Rule: When in doubt, read the sentence aloud.If you pause naturally, you probably need a comma. If the sentence ends, you need an end mark.End MarksCommasApostrophes
This map organizes the three main punctuation categories tested on the TACHS: end marks, commas, and apostrophes. Each branch shows a specific rule with a quick example.

Comma Before a Conjunction in a Compound Sentence

A compound sentence joins two complete thoughts with a connecting word like and, but, or so. You need a comma before that connecting word. For example: "I studied for the test, and I felt confident." If you forget the comma, the sentence runs together and becomes harder to read.

SECTION 6

Worked Example: Finding the Error

Let's walk through a TACHS-style question together, step by step. Follow along and see how we use the 4-Step Error Check.

📝 Sample Question
Choose the underlined part that contains an error. If there is no error, choose D. (A) On tuesday, (B) Maria and her brother (C) walked to the library. (D) No error

Finding the Error Step by Step

Step 1 — Read the Whole Sentence

The sentence says: "On tuesday, Maria and her brother walked to the library." It makes sense as a sentence. Now let's look closer.

Step 2 — Check Capitalization

Look at part (A): "On tuesday." Wait—"tuesday" is the name of a specific day of the week. Days of the week are proper nouns and must be capitalized. This is the error!
"tuesday" should be "Tuesday"

Step 3 — Verify the Other Parts

Part (B), "Maria and her brother," is correct—"Maria" is capitalized because it is a name. Part (C), "walked to the library," ends with a period, which is the correct end mark for a statement. Nothing else is wrong.

Step 4 — Choose Your Answer

The error is in part (A). Select (A) as your answer.
Answer: (A) — "tuesday" must be capitalized to "Tuesday" because days of the week are proper nouns.
SECTION 7

Common Traps and How to Avoid Them

The TACHS uses certain tricks to trip you up. The table below lists the most common traps and gives you a strategy for each one.

Top 5 TACHS Error Traps
TrapExampleHow to Beat It
Capitalizing seasons"We went camping in Summer."Seasons are NOT capitalized unless they start a sentence. It should be "summer."
its vs. it's"The cat licked it's paw.""It's" means "it is." For possession, use "its" (no apostrophe).
Missing comma after intro"After the game we ate pizza."Put a comma after the intro phrase: "After the game, we ate pizza."
Question with a period"Where is my backpack."If it asks something, it needs a question mark: "Where is my backpack?"
No-error trickA perfectly correct sentenceDon't overthink. If every part follows the rules, choose "No error."
✦ KEY TAKEAWAY
Think of error-identification questions like a game of "Spot the Difference." You have a mental picture of what a correct sentence looks like. Compare the test sentence to that picture. If something doesn't match, that's your answer. If everything matches perfectly, choose "No error" and move on!
SECTION 8

Looking Ahead: More Complex Rules

The basic rules covered in this lesson will handle most TACHS questions. But as you continue growing as a writer, you will meet more advanced punctuation and capitalization challenges. Here is a sneak peek at what comes next.

Basic vs. Advanced Punctuation & Capitalization
What You Know NowWhat's Coming Next
Commas in a series of three or more itemsSemicolons to join two related complete sentences
Apostrophes for singular possession (the dog's bone)Apostrophes for plural possession (the dogs' bones)
Capitalizing proper nouns like names and placesCapitalizing titles of books, movies, and songs correctly
Commas after introductory wordsCommas to set off appositives (extra information about a noun)

Don't worry about memorizing these advanced rules right now. Focus on mastering the basics first. Once you feel confident with commas, end marks, apostrophes, and capitalization, you will be ready to tackle these more advanced skills in high school English classes.

SECTION 9

Practice Problems

Try these five problems on your own. For each one, decide which underlined part contains an error—or choose "No error." Then check the answer and explanation below.

PROBLEM 1 — CONCEPTUAL
Which of the following should always be capitalized? (A) seasons like summer and winter (B) days of the week like monday and friday (C) common nouns like school and park (D) connecting words like and and but
PROBLEM 2 — BASIC
Find the error: (A) My aunt lives (B) in denver, colorado (C) and she loves hiking. (D) No error
PROBLEM 3 — INTERMEDIATE
Find the error: (A) After the concert (B) we walked to the car (C) and drove home safely. (D) No error
PROBLEM 4 — APPLIED
Find the error: (A) My dog buried (B) it's bone (C) under the big oak tree. (D) No error
PROBLEM 5 — CRITICAL THINKING
Find the error: (A) On January 15, 2024, (B) mayor Johnson (C) announced a new park for the city. (D) No error
SUMMARY

Lesson Summary

To spot errors on the TACHS, remember the key rules. Every sentence needs an end mark that matches its purpose: a period for statements, a question mark for questions, and an exclamation point for strong feelings. Use commas in a series of three or more items, after introductory words or phrases, and before a conjunction in a compound sentence. Apostrophes show possession or form contractions—but remember that "its" (possessive) has no apostrophe.

For capitalization, always capitalize proper nouns (names of people, places, days, months, holidays, and languages) and titles that come before a person's name. Do not capitalize seasons or general common nouns. Use the 4-Step Error Check: read the whole sentence, check capitalization, check punctuation, then choose your answer. If everything follows the rules, "No error" is a perfectly valid choice.

Varsity Tutors • TACHS Written Expression • Recognize punctuation and capitalization errors (as tested)