Tom was over there. His red clothes stood out clearly ________ the snow.

This field of scientific research remains________.

The number of the employees has grown from 1,000 to 1,200.This means it has risen ________ 20 percent.

(2013·辽宁五校一模)The little child  ________ go out alone at night, so he ________   walk in the dark that night.

I can hardly imagine ______ little children can work out the problem in _____ short a time.