1.His salary as a driver is much higher__(B)
A than those of a teacher B than that of a teacher
为什么不选A?

2.——（A）all the poems I have read recently,his seems best.
A of B among C in D about
为什么不选B?

3.he came back late,__(D)which time all the guests had alread left.
A after B during C at D by
为什么不选B


谢谢高手啦 麻烦给我详细解答一下

1. 因为B中that指代的是salary薪水，是单数形式，A中的those是复数形式
2. 这句的正常语序应该是his seems best （A）all the poems I have read recently.这样看你就会明白了，best of all对吧，没有说best among all的
3. 这句是非限制性定语从句，重点就在于all the guests had alread left，用的是过去完成时，by加一个时间就是用完成时，这儿的by加的是过去的一个时间所以应该用过去完成时，而且可以通过句意选：截止到他回来的那个时间，所有的客人都已经离开了。