电泵井的正常启停机组由值班采油工进行操作,发生故障时必须由持有()的专业人员进行处理。
参考答案:“电泵操作证”
Our monitor didn’t see all the students, because was ill and didn’t come to school today.
A.someone
B.no one
C.anyone
D.everyone
WHO规定的青春期为
A.≥20岁B.15~20岁C.10~19岁D.13~15岁E.10~13岁