1.直到听到闹钟的铃声我才醒来 （not...until)
Not until I heard the alarm clock ringring did I wake up.
或者不用倒装,正语序
I didn't wake up until I heard the alarm clock ringring.
2.正因为你在做作业,所以我才告诉你这件事（强调句）
It was because you were doing your homework that I told you this matter.
3.虽然他很严肃,但是我发现和他相处好并不难 (it作形式宾语）
Although he is a very serious person,I didn't find it difficult to get along with him.
4.不要再责备他了,他不是故意伤害你的 (on purpose)
Don't blame him any more.He didn't hurt you on purpose.
5这是我第一次出席这么重要的会议纪 （it is the first time that)
It is the first time that I have attended such an important conference/meeting.