We decided not to climb the mountains because it was raining ＿＿＿. 

The Internet is increasingly accessible at school and at home. _____many parents and teachers are sometimes not as prepared as we should be to warn children about Internet threats.

 Once he makes up his mind to do something, he will devote himself _________to it.

----- Now that you like the portable personal computer so much, why not buy one? It is of great use to your work. ---- Well, I can’t afford _____ computer at present．

______ acupuncture developed, the simple “bian stones” were replaced first by stone  and pottery needles, and ________ by metal needles.