—I phoned you at 7:00 this morning. But there was no answer.

—Well, maybe I _________ morning exercises at that time.

A．was doing

B．did

C．is doing

D．would do

3周前刚注射过丙种球蛋白的儿童要注射麻疹疫苗应推迟（）

A.4周

B.2周

C.3个月

D.6个月

E.2个月