My bicycle is nowhere to be found. Who ___ have been using it?
A. should B. must C. could D. might
He cut off the electricity immediately he found the dangerous situation, thus ____ a fire accident.
A. prevented B. to prevent C. would prevent D. preventing
But at other moments you will find him gentle and weak, _____ he cries about the lost lives of people drowned in ships that have sunk.
A. as with B. as for C. as to D. as when
They form a polar molecule, ____ is, ____ with a slightly positive end and a slightly negative end.
A. which; that B. it; one C. that; one D. one; that
They find themselves surrounded by colorful rocks, fishes, seashells and plants, all ____ slowly in the blue water.
A. waving and moving B. waved and moved
C. waved and moving D. waving and moved
Even though the pure water is ____ gives sea water its main properties, the salinity of sea water affects both its weight and freezing point.
A. the one B. which C. what D. that
