639.The group is made up ______ five students.And they are studying hard to make up ______ the lost time.

A.of;of

B.for;for

C.of;for

D.for;of

640.I was wandering ______ the streets when I caught sight of a tailor's shop.

A.across

B.through

C.by

D.past

639.答案是C;

此题考查make up 构成的短语。Make up组成，构成，化妆，陪着，编造；be made up of由…组成；make up for lost time弥补失去的时间。注意:make up the missed lessons 补课。

640.答案是B;

wander through the street在街上徘徊。