Tier 1 · Writing Lab
Tier 1 — Sentence
The unit everything else is built from. A sentence that is complete, agrees with itself, and is punctuated so a reader knows where it starts and stops.
By the end of this tier you will be able to
- Tell a complete sentence from a fragment, and say what is missing
- Recognize and repair run-ons and comma splices
- Make subjects and verbs agree, including when a phrase separates them
- Punctuate and capitalize so the reader is never slowed down
- Choose correctly between commonly confused words
What this tier covers
- Complete sentences
- Fragments
- Run-ons and comma splices
- Subject-verb agreement
- Punctuation
- Capitalization
- Commonly confused words
About 40 minutes. Nothing here is graded.
How this works
Read this first. Everything after it assumes these ideas.
What makes a sentence complete
A complete sentence needs three things: a subject, a main verb, and a thought that can stand on its own. Miss any one of them and you have a fragment — no matter how long the group of words is.
That last point is where most people go wrong. Length feels like completeness. It is not. "The manager, who had worked there for eleven years and knew every customer by name" runs to sixteen words and is still a fragment, because the manager never does anything.
The test
Read the group of words aloud on its own. If a listener would wait for the rest, it is a fragment.
The two opposite errors
A fragment is too little — a piece of a sentence sent out alone. A run-on is too much — two complete sentences jammed together without the punctuation that separates them.
A comma splice is the most common run-on and the hardest to see, because a comma looks like it is doing the job. It is not strong enough. Two complete sentences need a period, a semicolon, or a comma plus one of seven joining words.
| Join | Use it when | Example |
|---|---|---|
| Period | The two ideas can stand apart | The printer jammed. I used the one upstairs. |
| Semicolon | The ideas are closely related and equally weighted | The printer jammed; I used the one upstairs. |
| Comma + for, and, nor, but, or, yet, so | You want to name the relationship | The printer jammed, so I used the one upstairs. |
| Make one clause dependent | One idea sets up the other | Because the printer jammed, I used the one upstairs. |
Agreement, and why it is really a subject problem
Subject-verb agreement errors are usually not verb errors. They are subject-identification errors. In "The box of files ___ on the counter," the subject is box, not files — files sits inside a prepositional phrase, and a phrase never changes the subject.
Cross out every prepositional phrase before you choose the verb. The sentence gets shorter and the answer gets obvious.
- Each, every, either, neither, and words ending in -one or -body are singular
- Two subjects joined by and are plural
- With either/or and neither/nor, match the verb to the nearer subject
- Along with, as well as, and in addition to do not make a subject plural
A worked example
A real draft, improved one decision at a time. The order of the moves is the skill.
Repairing a sentence that has three problems at once
A note left for a supervisor. Every error in it is one this tier covers.
The draft
Because the delivery arrived late, we couldn't finish the order, the boxes of inventory is still on the dock.
The thinking, in order
Find each complete sentence first
There are two: "we couldn't finish the order" and "the boxes ... [are] still on the dock." The opening clause starts with Because, so it is dependent and belongs to the first one.
Name the join that is wrong
The comma after "order" sits between two complete sentences. A comma alone cannot do that — this is a comma splice.
Choose a repair that fits the meaning
The second statement explains the consequence of the first, so they are closely related and equally weighted. A semicolon fits better than a period here.
Now check agreement, with the phrases crossed out
"The boxes of inventory" — cross out "of inventory" and the subject is boxes, plural. So the verb is are, not is.
The revision
Because the delivery arrived late, we couldn't finish the order; the boxes of inventory are still on the dock.
TakeawayWork in that order every time: find the complete sentences, fix the joins, then check agreement. Fixing agreement first wastes effort on sentences you are about to restructure.
Guided practice
Structured practice with support. Nothing here is graded.
Drill each skill on its own before mixing them. Every question explains why the wrong answers are wrong — that explanation is the part worth reading, especially on the ones you get right by instinct.
Independent practice
On your own now. Your draft stays in this browser until you copy it somewhere.
Independent practice for this tier is the Sentence Skills engine. Filter to one skill, work a full set, and read the reasoning on every question — including the ones you get right.
Open Sentence Skills →Check yourself
Not recorded, not a grade. Use it to decide whether to move on or go back.
Tick what is true of your own writing right now. Anything left unticked is what to work on next — that is the whole purpose of this list, so leaving boxes empty is useful rather than a failure.
0 of 5 ticked. Not a score, and not recorded.