21．Zach Howell, president of Tsinghua University ____ the same thing two years ago. But he says this year is "completely different."
A．should say B.must have said C.could have said D.might say
22. I do not usually celebrate my birthdays until I met him._____,I do not like any big party because I am not that good at small talk.
A. On the whole B. On average C. In addition D. In other words
23. The customer would be urged to see a doctor. If the man did not have a doctor, then a visit to _________ would be set up.
A. that B. one C.whom D.it