路堑开挖应该遵循()的顺序，严禁掏底开挖。
A.从左至右
B.从右至左
C.从下而上
D.从上而下
参考答案：D
If the dog hadn't woken us, we wouldn't have noticed the fire and it _______ to the house next door. [ ]
A. could spread
B. should have spread
C. would spread
D. might have spread
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