Question

1.( ) Tom with his sister __________ going to swim tomorrow.

Answer 1

1 B Tom 是真正的主语,其实你可以看作是Tom is going to swim tomorrow with his sister.这样就好理解了.当然这仅限于with,如果是Tom and his sister 就要用are 了

2 on 有一些固定用法.例如on the bike,in the car ,on the bus ,at the boat等

3 be 感觉有点牵强,不过也没有更合适的了

4 be 把动作改成了状态