— Believe it or not, my sister and I are twins.

— Oh, you must have had the case _____ you were taken for your sister. [ ]

A. which

B. whose

C. where

D. whom

两只相同的杯子置放在窗前，分别盛放等高的水和汽油，一段时间后，两杯中的液面如右图所示．这个事例说明液体的蒸发跟液体的（　　）

A．表面积大小有关

B．温度高低有关

C．表面空气流动快慢有关

D．种类有关