Question

The teacher and writer ________ doing morning exercises this time yesterday．

1. A.
   is
2. B.
   was
3. C.
   are
4. D.
   were

Answer 1

B
and后面的名词没有修饰语，由此可知the teacher and writer所指的是同一个人．根据时间状语this time yesterday可知用过去进行时．