He is a student and_______ name is Maria. [ ]
A. he
B. his
C. him
D. her
答案：B
因数的末尾有2个0，积的末尾一定也有2个0。[ ]
在下列流量计中，存在压力损失的是（）.
A.超声波流量计
B.电磁流量计
C.激光流量计
D.刮板流量计
