_________ is a growing world problem, and nowadays the United Nations and its member countries _________hard to deal with it．
#6050
A
Desertification; are working
B
Desertified ; worked
C
Desert; work
D
Desertification; have worked
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Language has always been —— as the phrase goes —— the mirror to society. English is no ______
#5554
A
explanation
B
excuse
C
exception
D
expectation
．Lily succeeded, for she had made the greatest _________ and got over plenty of difficulties.
#7082
A
force
B
strength
C
effort
D
energy