1. It has been 3 years since he got married.

　　他结婚3年了。

　　2. It will be a long time before everything returns to normal.

　　(将)要很长时间一切才恢复原状。

　　3. It was 3 hours before the fire was put out.

　　过了三个小时大火才被扑灭。

　　4. It won’t be long before he comes back.

　　不会要很久他就会回来的。

　　5. It is/was the first (second) time (that) I have been/had been here.

　　这是我第一(二)次我来这里。

　　6. It makes no difference to me when the sports meeting will be held.

　　运动会什么时候举行对我说无关紧要。

　　7. Two many students find it difficult to get into the classroom on time in the morning.

　　太多学生觉得早上按时到校很难。

　　8. It is no use/good learning without practice.

　　学而不用没有用处/不好.(光学不练假把式)

　　9. It was Oct 1st, 1949 when PRC was founded.

　　中华人民共和国成立的时间是1949年10月1日。

　　10. It was on Oct 1st, 1949 that China was founded.

　　中华人民共和国就是在1949年10月1日成立的。