21. My room is a little untidy. So I’ll tidy it ______.
A. to             B. on            C. in             D. up
22. He likes collecting things and he has many       at home .
A. collect                 B. collection
C. collections              D. collecting
23. Her interest is playing table tennis and her brother is       
in playing basketball.
A. interesting             B. interested
C. interest                D. interests