Some compound expressions are used as conjunctions. These are called compound conjunctions. Common examples are given below.
As well as
The doctor as well as his wife attended the party.
The manager as well as the secretary has signed the papers.
As soon as
The students began to talk as soon as the teacher left the classroom.
The passengers rushed to board the train as soon as it arrived.
As if and as though
Both of these expressions have the same use.
She started laughing as if she was insane. (She is not insane)
He speaks as if he is rich. (He may be rich.)
They talked as if they were scholars.
Note that the present tense is used here to suggest that the comparison is true. A past tense, on the other hand, is used in unreal comparisons.
He will play even if he is unwell.
I cannot admit you even if you have a ticket.
In order that
They climbed up a tree in order that they would get a better view of the procession.
You can borrow my car provided that you return it before midnight.
He started early so that he would reach early.
On condition that
I will lend you my camera on condition that you return it tomorrow.