Incomplete sentences
A sentence must have a main verb. If it does not have a main verb, it is a subordinate clause, not a sentence, or independent clause. Subordinating conjunctions are often used to join a subordinate clause to an independent clause, so if there is a subordinating conjunction, there must be two clauses - otherwise, again, it's not a complete sentence.
Sentence? |
Explanation |
Run! |
This is a sentence because there is a main verb with a tense (imperative). |
Running round the park. |
This is not a sentence. 'Running' is a gerund (verb being used as a noun), so there is no main verb. |
Running round the park makes me tired. |
This is a sentence, or independent clause. 'Makes' is the main verb. |
Since I have been running round the park for thirty minutes. |
This is not a sentence. 'Since' is a subordinating conjunction, so it must connect a subordinating clause to an independent clause within one sentence. There is no independent clause. |
Since I have been running round the park for thirty minutes, I am tired. |
This is a sentence. There is an independent clause (I am tired), with the main verb 'am'. |
Watch here for a video explanation: https://www.youtube.com/watch?v=SQ8faQgi6UE
Misuse of comma
A comma is used to make a pause within a sentence, often between a subordinate clause and a main clause. It is not strong enough to link two independent main clauses. Instead, you should use a conjunction, a full stop (period) or a semi colon.
Today we are learning about punctuation, the comma is tricky.
Today we are learning about punctuation; the comma is tricky.
Today we are learning about punctuation, but the comma is tricky.
Today we are learning about punctuation. The comma is tricky.
The first sentence above is wrong, because there are two independent clauses (each clause has a main verb and can exist on its own).
See here for a video explanation: https://www.youtube.com/watch?v=eC-CSmOIUBA
Overuse of 'there is/are'
As you probably know, 'there is/are' is used to explain that something exists or happens in English. For example:
'There are five books on the shelf' means 'Five books exist on the shelf'.
We do not put these two structures together: 'There are five books exist on the shelf'.
In fact, this sentence is grammatically incorrect. We could make it correct by adding a relative pronoun: 'There are five books that exist on the shelf' - but we don't need to. It's easier to write: 'Five books are on the shelf.'
When proofreading, check whether you are overusing 'There is/are'.
Let's practise proofreading. Decide whether these sentences are grammatically correct or whether they are incomplete sentences, misuse the comma, or use 'There is/are' incorrectly.