闸门止水失效，可造成（）。
A.闸门漏水
B.闸门振动
C.闸门及埋件空蚀、磨蚀
D.闸门挤压
参考答案：A, B, C
灰太狼家要给新买的房子铺地板砖，灰太狼打算用面积0.04平方米的地板砖铺地需要500块，红太狼坚持要用面积是0.25平方米的地板砖铺地，请你帮她算一算一共需要多少块？
— Why are you so late? I _____ for more than an hour.
— I'm terribly sorry. I overslept and missed the bus. [ ]
A. am waiting
B. was waiting
C. have been waiting
D. will be waiting
