Beijing is cold this time _____. You need _____ warm clothes if you go there.          [ ]

A. of the year, to pack

B. of year, packing

C. of year, pack

D. of year, to pack

个体乳酸阈水平可用来评定运动员的( )能力。

A．无氧运动

B．有氧运动

C．缓冲血乳酸

D．ATP-CP供能系统