第三个馏出的是( )

A．单萜烯
B．单萜酸
C．单萜醇
D．单萜醚
E．倍半萜 采用分馏法分离上述化合物时，馏出顺序为

________ I had walked for six hours, I was tired out.

A．After

B．Before

C．When

D．As