— How did you sleep last night?

— Not very well. I ________ too late preparing a report for the meeting.[ ]

A. made up  

B. stayed up 

C. kept up   

D. turned up

以下物质分子中不能以简单扩散方式透过细胞膜的是（）。

A.H₂O

B.O₂

C.尿素

D.葡萄糖