21._______the rain falling so hard, it becomes more and more difficult to carry on the rescue work.
A. Since B. With C. As D. For
22.It is reported that two schools, _______are being built in my hometown, will open next year.
A. they both B. which both C. both of them D. both of which
23. As is reported, a big fire broke out and out of _______ control, _______southwest of the city of Sichuan.
A. the, the B. /, the C. the, / D. /, /
