检修闸门只有（）两种工作状态。
参考答案：全开和全闭
After I my homework, I went out to an aquarium.[ ]
A. was doing
B. did
C. does
D. would do
五行中，"水"的"子"行是（）
A.金
B.木
C.水
D.火
E.土
