CAUTION: NOT A TEACHER
Great question!
(1) I think that you could speak English without subordinating conjunctions, but it
would not be so smooth.
(a) I like usingenglish.com. The reason is that I learn a lot here.
(i) Isn't it smoother to say "I like usingenglish.com because I learn a lot here.
(b) I ate dinner. Then I watched TV.
(i) I ate dinner before I watched TV.
(c) I ate dinner. At the same time, I watched TV.
(i) I ate dinner while I watched TV.
(2) I think that you have gotten the idea. Am I right?
(3) The teachers here appreciate it if we learners use a whole sentence. If you used
"in order that" in a sentence, maybe the teachers would be happier. I checked a
good book called Practical English Usage by Mr. Michael Swan. He tells us that
"in order that" or "so that" are subordinating conjunctions that help us express
a purpose:
(a) Mr. Swan's example: She is staying here for six months so that she can perfect
her English. (ONLY MY OPINION: I believe that we could also say: She is staying
here for six months in order that she may perfect her English.) Mr. Swan says that
"in order that" and "may" are more FORMAL than "so that" and "can."
(b) IF we did not have subordinating conjunctions, it would take many more words
to express that sentence. Maybe something like:
She is staying here for six months. Her purpose for staying here for six months is to
perfect her English.
