____ printed, this science fiction will be popular among the students.
| A．Before | B．Unless | C．When | D．Once |
26．—Why are your hands so dirty?
—I________in the garden．
| A．was working | B．have worked | C．worked | D．have been working |
25．—Why not open the windows to let_____cool air in?
—I'd rather you didn't_____air in our town is terribly polluted．
A．a；The B／；The C．/；/ D．the：/
24．It is a rule in our school that no books______out unless you have a library card.
| A．must be taken | B．might take | C．can be taken | D．should be taken |
23．Naturally I will come to you for advice whenever I feel I need________.
| A．them | B．one | C．some | D．Few |
22． Today，_____rapid transportation and communication, the whole word seems to be smaller．
A．regardless of B．in 
spite of C．instead of D because of