Schools across China are expected to hire 50,000 college graduates this year as short-term teachers, almost

three times the number hired last year, _____ reduce unemployment pressures. [ ]

A. help

B. to have helped

C. to help

D. having helped

大剂量肾上腺素静注，血压的变化是（）

A.收缩压和舒张压均缓慢、持久升高

B.收缩压上升，舒张压不变或稍下降

C.收缩压上升，舒张压上升，脉压变小

D.收缩压上升，舒张压上升不明显，脉压增大

E.收缩压上升，舒张压下降，脉压增大