Question

All________been finished．We can have a rest now．

1. A.
   have
2. B.
   has
3. C.
   had
4. D.
   are

Answer 1

B
分析：此处all指的是“所有的事情”，要看成单数，所以选B项。(延伸) all of，half of，the rest of，two-fifths of，some of，most of要看of后面的名词性质，没有of时，就要从上下文来看这些词所指的是复数概念，还是单数概念。