1. It depends on whether we have enough time .

10. She sings　 songs　 as if　 she is a bird .

答案：1. can 改为could 2.去掉so 3.will come改为 comes 4. very改为 so 5.as soon as 改为when 6.was 改为is 7.than 之后加上that of　 8.than　 后加 those in　 9.whatever改为 wherever 10. is改为 were

9.Whatever there is plenty of sun and rain , the fields are green .

8.The streets in Nanjing are wider than Shanghai .

7.The playground of our school is larger than their school .

6.It was three months since he came to our school .

5.Tom had gone out as soon as his mother got home .

4.He was very foolish that he didn't pass such an easy exam .

3.He won't go out until his mother will come .

2.Since her husband had died , so she had to support　 her family .