Wolf-Rayer星的寿命约为（）
A、几百万年
B、几千万年
C、几亿年
D、几十亿年
参考答案：A
测定中心静脉压时，测压玻璃管的零点应在（）
A.锁骨中点水平
B.剑突水平
C.胸骨角水平
D.右心房中点水平
E.右心室中点水平
Nowadays we are often filled with some apparently _______ suggestions made by so-called experts on
how to keep in good health. [ ]
A. appropriate
B. aggressive
C. concrete
D. contradictory
