i like you
I will do what i can do for you
从属连词（不做成分）that（无意义）,if/whether（与or not /to do连用,介词后用）,连接代词who（主/宾）,whom(宾),whose（定）,which(主/宾), what(主/宾)连接副词：where,when,how，why
i don't know whether he likes you
i konw who he is.
I was very sorry to hear (昨天他生病了)-that he had a fever yesterday.
the teacher is talking about -(月亮围着地球转)-that the moon goes around the earth.
I think of (是否我们应该去看电影)-whether we should go to see a film.
he says that he likes you
he said that he liked you
he said that light travels faster than sound