There()a pair of shoes under the bed.A.are.B.isC.

题目

There()a pair of shoes under the bed.A.are.B.isC.
There()a pair of shoes under the bed.A.are.B.isC.am What()in the bathroom.A.are.B.is C.am
老师讲答案是am两题都是am和is在什么情况下用区别是什么：

答案

　　B.is
　　am主语一定是I；is主语为第三人称单数