问题描述：
"that must be a mistake" "no,it______a mistake"
A)must not be
B)needn't be
C)cannot be
D)would not be
请说明选择的原因,为什么不能选别的答案
2)the surroundings a child grows up in usually______an effect on his development
A)have
B)had
C)do
D)has
请说明选择的原因,为什么不能选D和B
A)must not be
B)needn't be
C)cannot be
D)would not be
请说明选择的原因,为什么不能选别的答案
2)the surroundings a child grows up in usually______an effect on his development
A)have
B)had
C)do
D)has
请说明选择的原因,为什么不能选D和B
问题解答：
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