本科生第二课堂活动实行学分化管理，要求全校非医学类专业本科生在校期间至少获得几个学分（）
A.5个
B.2个
C.4个
D.3个
参考答案：B
The train _______ at the present speed until it reaches Beijing at about 6 :30 am.
A．went
B．has gone
C．goes
D．will be going
实际操作中操作工常易发生哪些违章的错误操作？
