18. Classification is a useful ____? to the organization of knowledge in any field.
A. meansB. approachC. modeD. manner
19. The human race has already paid a heavy price for its slow ____?to environmental threats.
A. responseB. responsibility
C. resolution D. resistance
20. We have a high regard for Prof. Joseph because he always ____?his principles.
A. lives onB. lives up to
C. lives through D. lives with
21. My grandfather accidentally ____? fire to the house.
A.putB. tookC.setD. got
22. We enjoyed the holiday ____? the expense.
A.exceptB. besides
C. in addition toD. except for
23. If you want children to work hard you must ____? their interests instead of their sense of duty.
A. appeal toB. look intoC. give rise toD. go in for
24. Basically a robot is a machine which moves, manipulates, joins or processes ____? in the same way as human hand or arm.
A. characters B. components
C.catalogues D. collections
25. Of course, talking about something which affects them personally is ____?motivating for students.
A. chieflyB. correctlyC. currentlyD. eminently