mình làm rồi mong các bạn sửa giùm
he wasn't feeling well , so he didn't do well in the exam
if he was feeling well, he would do well in the exam
2 Tom speaks English very well
tom has studied English for a long time.
3 I haven't written to him for a long time
it is a long time since the last time I wrote to him.
4 I'll see you next week unless something unexpected happens
if something unexpected doesn't happen, I 'll see you next week.
5 this is the biggest fish I have ever seen
never before I have seen a fish bigger than this.
6 i'm sorry i can't understand anything
I wish I could understand something