—Isn't it hard to drive downtown to work?—Yes,that's why I________to work by train.
Jenny was shaking and crying at the corner of the street as if she __________ frightened by somebody.
A healthy lifestyle is often considered to be __________ exercise, mood and diet, and so on.
Jack wasn't saying anything, but the teacher smiled at him __________ he had done something very clever.
The experts were doing their experiment in the lab, __________ what happened outside.
The old man stood by the window, __________ his eyes on the people playing in the park.