不会使离心泵的必需汽蚀余量改变的是()。
A.泵进口部分形状
B.泵的转速
C.泵的流量
D.吸入液体温度
参考答案:D
She says that her brother is good _____ swimming. [ ]
A. for
B. at
C. to
D. of
卵裂方式完全是由卵黄的含量决定的。