First we have noun phrases, which are not complete sentences (they have no full verb--some call them fragments). For example:
This is a noun phrase (NP), but it isn't a complete sentence. What is the dog doing? What is happening to the dog? We don't know because it's a fragment. However, in English, NPs can be subjects:
(1) A dog bit his finger. (SUBJECT, VERB, OBJECT)
NPs can also be objects:
(2) He bought a dog. (SUBJECT, VERB, OBJECT)
Both (1) and (2) are clauses (complete sentences). They are also simple sentences, but you want complex sentences if want to impress that TOEFL essay rater! One way to make complex sentences is to take simple sentences and then make them into NPs so you can make them the subject or object of a sentence. What to do? Well, there are a variety of ways to do this, but I'll talk about three.
Strategy 1: Add that if it doesn't follow a preposition
You can add that to the beginning of a sentence to make it act like a NP (some call this a complement).
(3) He dreamed [that a dog bit his finger].
(4) His wife was upset [that he bought a dog].
You can also make these the subject, but that form is more rare and a bit more complicated, so I'll explain it in another post in the indeterminate future.
Strategy 2: Change the main verb to the -ing form, and change any pronouns to the possessive
The -ing form of the verb can act like a noun (we call this the gerund). Once the verb is a gerund, you need to change any subject pronouns into possessive pronouns:
- I --> my
- he --> his
- she --> her
- it --> its
- we --> our
- they --> their
If it's not a subject pronoun, then don't mess with it.
(5) He dreamed about [a dog biting his finger].
Technically, "a dog's biting his finger" is correct but no human I know says this--you can find it in writing sometimes, but when I searched the COCA it was fairly rare.
(6) His wife was upset by [him buying a dog].
(he becomes him and bought becomes buying)
Strategy 3: Add the fact that or the idea that if it follows a preposition
This one is a little bit trickier, but still very useful. I recommend doing a corpus search for
the fact|idea|notion that
After you've done that, then you can hopefully get an idea about when and where people use these expressions. Here are some examples I made:
(7) He dreamed about [the fact that a dog bit his finger]. (NOTE: It must be a fact to use the fact that.)
(8) His wife was upset by [the fact that he bought a dog].
These three strategies are a good starting point for making more complex sentences. Now go out and impress one of those essay raters!
Have a good one, and good luck out there.