In ______ time, those mountains will be covered with trees.

A. few years    B. few year    C. a few years’    D. a few year’s

In ________ time, those mountains will be covered with trees, too.

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In a few years' time, those mountains ________trees.

A. have been covered with

B. are covered by

C. will be covered with

D. will cover by

I believe that those mountains ________ trees in a few years' time.

A. are covered with

B. will be covered with

C. are covering by

D. will cover by