21. When he was abroad on business, he _____ some spoken English.

A. picked out         B. picked up                 C. brought up               D. brought down

22. ____________your composition carefully, some spelling mistakes can be avoided.

A. Having checked               B. Check               C. To check                  D. If you check

23. ____________ to the left, you will find the path________ to the park. .

A. Turn; leading     B. Turned; to lead         C. Turning; leading              D. Having turned; led