i'm not a native speaker but i think "what makes you thinking" is more usable in spoken English.

"That" is English, use in this sentence (meaning ",что" in Russian) is used the same way it is used in Russian: I think that she is here Я думаю ,что она здесь Now, you can remove the "that" and the sentence means exactly the same thing. There is no difference between saying: She said that she has no time And saying She said she has no time. Both mean "она сказала, что нет времени". Now, using "that" it is used more in written language than spoken, but it does not mean that it is more formal. It is only used in written English more than in spoken English because in spoken English you can make pauses and change tone, something you cannot do in written language as much as in spoken language. I hope this helps. As for "so"... here, it means "так". For example: A: Do you think that there is a God? B: I don't think so (I don't think that way / that is not what I think я не так думаю) "If you do so, you will be here earlier" "If you do it this way, you will be here earlier" I hope this helps...