The cartoons made by the artists sell best, but several years ago no one could imagine how great a role he _____ in the field.

Not until the early years of the 19th century ________ what heat was.[ ]

How did you find your visit to 2010Expo/—I enjoyed it very much. It was ________that I had expected.

She prefers ________ on the Internet rather than ________ in the supermarket. [ ]

下列各语句中加横线词语使用恰当的是（ ）