从溴乙烷制取1,2﹣二溴乙烷,下列转化方案中最好的是( )
A:CH3CH2Br
B:CH3CH2BrCH2BrCH2Br
C:CH3CH2BrCH2=CH2CH2BrCH3CH2BrCH2Br
D:CH2=CH2CH2BrCH2Br
My uncle ________ come here tonight, but he isn't ________ home.
对下面的一则公益广告进行点评,不超过30字。
双面用,不丢面。(倡导节约用纸广告)