砌块建筑在相邻施工段之间或临时间断处的高度差不应超过( )楼层。
A．2个
B．1个
C．3个
D．4个
参考答案：B
—Kitty, will you go to see Spider-Man 3 with us this evening?
—Sorry. I ______ the film already. [ ]
A. saw
B. have seen
C. had seen
组织：结合所学专业谈谈如何上好一节课
