1.has been 和have been的区别与用法.
主语是I,we或者是复数形式的都要用 have been
主语是he,she,it 或者是其他单数形式的用has been
2.-Are there any snakes in your hometown?
-No.but in the past snakes were very _____.
A.dangerous B.normal C.common
选C
----你的家乡有蛇吗?
----没有,但是在过去很常见.
a的意思不对.b的意思是正常.c表示大多数情况.