如图所示的直观图的平面图形ABCD是( )
A:任意梯形
B:直角梯形
C:任意四边形
D:平行四边形
Lincoln's mother did what she can him.
(2015•安徽)某实验小组在探究光的折射规律时,让一束光从空气斜射如玻璃水槽内的水中,看到如图所示的现象: