1. 去掉on
2.stood→standing或在stood前加who
3.buy→bought
4.in→for或to
5. but→and或so
6. Unfortunate→Unfortunately
7.在hard前加a
8. him→them
9. alone→lonely
10.covered→covering
略
以下标有题号的每一行均有一个错误，请找出，并改正。
1. 去掉on
2.stood→standing或在stood前加who
3.buy→bought
4.in→for或to
5. but→and或so
6. Unfortunate→Unfortunately
7.在hard前加a
8. him→them
9. alone→lonely
10.covered→covering
略