当采用机械开挖基坑时，应在基坑底面标高以上保留（）厚的土层采用人工清底
A. 0.10m～0.15m
B. 0.15m～0.20m
C. 0.15m～0.30m
D. 0.20m～0.30m
查看答案
The wife cried bitterly when she called her husband because _________________.
A. she was told she was not the daughter of her father.
B. she met some difficulties.
C. their cat was killed by the dog.
D. their kid was ill.
"Wolf" is the name of __________.
A. the dog
B. the cat
C. a girl
D. a boy
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