12)(2011·河北正定期末)The fact has worried many scientists ______ the earth is becoming warmer and warmer these years.

　　A．what B．which C．that D．though

　　13)We should consider the students' request ________ the school library provide more books on popular science.

　　A．that B．when C．which D．where

　　14)The scientists haven't found the evidence ________ human beings came from space.

　　A．which B．that C．what D．who

　　15)There is a common belief among them ______ rubbish can and should be put to good use.

　　A．which　　　 B．if　　　　 C．whether　　 D．that

　　16)I have no idea ______far the airport is from here.

　　A．what B．how C．it's D．that

　　17)The manager asked the question ______I would like to be his secretary.

　　A．if B．that C．whether D．how

　　18)______is a fact______ English is being accepted as an international language.

　　A．It；that B．That；that C．It；which D．As；that

　　19)The question has been raised at the meeting ______ each member country should share the expenses of the committee.

　　A．which B．if C．what D．whether

　　答案：活学活用：1)that 2)when/whether 3)where/how 4)that 5)that 6)that 7)whether 8)that　9)whose　10)that　11)C　12)C　13)A　14)B　15)D　16)B　17)C 18)A　19)D