II.单项选择(共15小题，每小题1分，计分15分)
21. The boy dived into the water and after _______ seemed to be a long time, he came up again.
A. what B. that C. it D. which
22. In the first half of 2002,the number of people with AID or ______with the HIV virus in China was reported to be 1 million.
A. infected B. infecting C. were infected D. to be infected
