Our teacher told us that pollution _____ a very serious problem in the world we live.

A. has be
B. had been
C. is
D. was
C
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科目:初中英語 來源:期末題 題型:單選題

Our teacher told us that pollution _____ a very serious problem in the world we live.

[     ]

A. has be
B. had been
C. is
D. was

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