—What were you doing when he ________“hello”to you?

—I _______in front of the blackboard.

A．was saying; read

B．was saying; was reading

C．said; read

D．said; was reading

治疗期前收缩的首要措施是（）

A、针对病因和诱因治疗

B、选用β受体阻滞剂

C、选用胺碘酮

D、选用美西律

E、选用介入治疗