The lack of eco-friendly habits among the public is thought to be a major _____of global climate change.

—Paul has gone abroad to try his luck.—In my _______, his decision is not wise.

I bought a sweater for only 50 yuan yesterday; it was a real        .

One advantage of living on the top floor of a high rise is that you can get a good______of the city. 

Computers are of great        to the development of science and technology.