孔雀石属于()
A.硅酸盐
B.硫酸盐
C.碳酸盐
D.卤化物
参考答案:C
What we need to do for the Chinese civilization is not to lie on past glories, but to ________ and around.[ ]
A. look forward
B. look up
C. look ahead
D. look into
选择天线时,郊区通常选择增益(),水平波束(),垂直波束()的天线
A.高,窄,窄
B.高,宽,宽
C.高,宽,窄
D.高,窄,宽