体外循环没有哪项作用()
A.泵血
B.气体交换
C.降低和升高血液温度
D.酸碱平衡
E.超滤
参考答案:D
I don't need _______ a new dictionary because I bought this one year ago. [ ]
A. buying
B. buy
C. to buy
D. bought
使用抛线法验电时,所用抛线须用截面积为()mm2的裸铜软绞线做成。