Li Yan feel well today. [ ]
A. don't
B. doesn't
C. isn't
答案:B
We had planned to finish the work before dark, but the heavy rain _____ us _____.
A.build, up
B.put, up
C.bake, up
D.hold, up
诊断螺杆泵故障可通过观察()的变化来诊断油井工作状况。
A、套压和静压
B、流压和静压
C、油压和套压
D、油压和流压