题目内容：

.it -------snows  in Shanghai in winter
A sometimes B usually
it is raining outside .-------- -------- your raincoat.
A  putting on B  put on 
i will tell him as soon as he -------
A returns back B returns 

优质解答

1 sometimes 虽然B 也说得通 可是上海的冬天只是偶尔下雪 还是sometimes跟符合实际一些
2 put on 祈使句
3 returns A的话 本身就是错的 return本身就是回来的意思 再加上back就重复了