Meimei listens to music _____. [ ]
A. sometimes
B. sometime
C. some times
D.some time
答案:A
侧钻井开窗部位以上套管必须试压,注水井测试压力为()
A.0.5MP
AB.10MPA
C.12MPA
正弦量的三要素是指它的最大值、角频率和相位。