21.When I spoke to him about our trip to China, he didn't make any _____ to your coming with us.
A.comments
B.references
C.inquiries
D.remarks
22.They were forced to _____ production for lack of raw materials.
A.cut across
B.cut in
C.cut off
D.cut back
23.The _____ of new scientific discoveries to industrial production methods usually makes jobs easier to do.
A.addition
B.association
C.application
D.affection
24.I'm happy to see you've made such a swift _____ from your illness.
A.recovery
B.restoration
C.renewal
D.retreat
25.The new traffic regulations will come into _____ in May.
A.efficiency
B.affection
C.effect
D.influence
26.The student couldn't _____ what the teacher was trying to explain.
A.grip
B.seize
C.grasp
D.snatch
27.A person of 18 should stop _____ on his parents.
A.dependent
B.independent
C.dependence
D.independence
28.There is virtually no _____ to this grammar rule.
A.except
B.accept
C.exception
D.acceptation
29.General Brown was older than any other officer in his regiment, but he was unwilling _____.
A.retiring from military service
B.to be retired by military service
C.to retire from military service
D.to be retired from military service
30.Your window wants _____, you'd better have it _____ this week.
A.cleaning, do
B.to be cleaned, do
C.cleaning, done
D.being cleaned, done