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單項選擇題

Every precaution must be taken to avoid （）.

A.sparking being taking place
B.to spark taking place
C.sparking to be taken place
D.sparking taking place

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It is obvious that the expansion of the water （）the increase of its temperature.

A.is due to
B.dues to
C.is because
D.is for

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An engineer, together with some motormen （）to help in the repair work.

A.send
B.sends
C.was sent
D.were sent