21. In face of failure, it is most important to keep up good state of mind.
A.不填；a B. a; 不填 C. the; 不填 D.不填；the
22.---Oh, it’s you! I ______ you.
--I have changed my hairstyle, and I’m wearing dark glasses.
A. don’t recognize B. hadn’t recognized
C. didn’t recognize D. haven’t recognized
