The phrases which are used as conjunctions are called compound conjunctions. Examples are: so that, provided that, as well as, as soon as, as long as, such that, in order that etc.
A compound conjunction may have two or three parts and they always go together. They are different from correlatives which are conjunctions used only in pairs. Examples of correlatives are: either…or, neither…nor, not only…but also.
She has got a car as well as a bike. (She has got not only a bike but also a car.)
Note the information structure: as well as introduces information already known to the listener; the rest of the sentence gives new information.
Note that after as well as, we use a noun or an –ing form. To-infinitives are possible, if the main clause also has them.
As well as breaking his back, he hurt his neck.
As if and as though
As if and as though have similar meanings.
He talks as if he is mad. (Perhaps he is mad.)
He talks as if he were/was mad. (He isn’t mad.)
Note that a past tense after as if/though indicates that a comparison is unreal.
The cat jumped in as soon as he opened the window.
He will pass the test provided that he works hard.
We eat so that we may live.
She is working hard so that she will pass the test.
You can share my room as long as you pay for your expenses.
After as long as, we use a present tense to refer to the future.
They held the function on a Sunday in order that everybody would be able to attend.
So that and in order that have similar meanings. So that is more common in an informal style.