A.were, were | B.was, was | C.were, was | D.were, was |
A.are | B.were | C.is | D.can be |
A.is ; is | B.are; are | C. is; are | D.are; is |
A.were, were | B.was, were | C.were, was | D.was, was |
A.was | B.might | C.make | D.did |
A.are used to prevent | B.are used to preventing | C.is used to prevent | D.is used to preventing |
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