21. If you don’t know that _____ failure is the mother of success, you are sure to be _____ failure in life.
A. /; / B. a; a C. a ; / D. /; a
22. _____ you have the chance to go to the university in the future, you must take it.
A. Will B. Would C. Could D. Should
23. --- You look very tired. _____ at all last night?
--- No, not really. I’m tired out now.
A. Do you sleep B. Were you sleeping C. Did you sleep D. Had you slept
