—Have you heard of the North Korea's nuclear test?

—Yes, ________ news came as ________ shock to me.

A. the; a  

B. the; the

C. a; a  

D. a; the

心房纤颤时，可出现的心电图改变是（）

A.P-P不等，P-R一致

B.P-P不等，P-R渐长

C.无P波，代之以"f"波，R-R不等

D.无P波，代之以"F"波，F与R成比例

E.P-P相等，R-R相等，P-R不等