__ different kinds of pianos, theworkers farther improved their quality

Frank ________ stamps in his spare time. It’s his hobby.

.Now,lots of universities have been set up in _________ used to be waste land.

Taiyuan, a city in North China, was struck by a heavy snowfall last week, ______ serious traffic problems

MrSmith is trying to hire a new secretary，who can both type and drive