I ___________ some English books.[ ]
A. have
B. has
C. had
D. having
答案：A
直流电法仪超前探测时，电极与底板接触不良，应通过（）方法增加导电性。
A.浇水
B.堆煤
C.接地
D.固定
降低转炉终点钢水中磷含量的措施有哪些？
