In a way, ________global warming is a challenge for man, so we must overcome it to build ________ fine world.

useful invention(发明) thecomputer is!

The employers often give the job to _______ they believe have work experience with a strong sense of duty.

though B【解析】试题分析：根据句意根据厂里的规章制度，如果你有医生的诊断书，你才能请假。故选B

Last week, only two people came to look at the house, ___ ___ wanted to buy it.