下列几何图形:
①角,②平行四边形.③扇形,④正方形,
其中轴对称图形是 [ ]
A. ①②③
B. ②③④
C. ①③④
D. ①②③④
答案:C
N、P、B、Mg等元素对油菜的生长具有()
A、同等重要性
B、有主次之分
C、直接作用与间接作用之分
D、可替代性
I really don't know how anyone can _____ your constant complaint; no wonder you have lost so many friends.
A.come up with
B.end up with
C.put up with
D.keep up with