4个月小儿可能的动作是（）。
A.会坐
B.会爬
C.会跑
D.会滚
E.会翻身
参考答案：E
He added a ______ to his letter by saying that he would arrive before 8 pm.
A. presidency B. prestige C. postscript D. preliminary
采煤机附近断电浓度为：（）
A、0.8%
B、1.0%
C、1.5%
D、2.0%
