整个教学工作的中心环节是（）
A.备课
B.上课
C.课外辅导
D.成绩评定
参考答案：B
_______of the children can get some presents that day.[ ]
A. Every
B. Each
C. Everyone
D. Nobody
Which type of link is generally used to connect shots of anchor chain（）.
A.Detachable
B.Open
C.Pear shaped
D.Stud link
