注意力缺陷多动症又称______综合征，其基本病面在于______。
参考答案：轻微脑动能障碍 脏腑阴阳失调
27. Now and then they would ______ our house and have a talk with us.
A．call on
B．drop in at
C．drop in on
D．drop in
GB175-2007《通用硅酸盐水泥》国家标准中对凝结时间有什么要求？
