Question

He received a letter with an unusual stamp on from his friend, which ________ his collection.

1. A.
   added up to
2. B.
   made up
3. C.
   added to
4. D.
   made up of

Answer 1

C
add…to表示“往……里添加”，add to表示“增加”，相当于increase，如add to your trouble。