As is often pointed out, knowledge is a two-edged weapon which can be used ______ for good or evil.
(2013·浙江,11)Half of ________ surveyed in 16 countries say they go first to their closest friend to share their deepest wishes and darkest fears.
Recycling is one way to protect the environment; reusing is ________.
The project requires close teamwork. ________ will be achieved unless we work well together.
(2013·全国Ⅱ,14)It's an eitheror situation—we can buy a new car this year or we can go on holiday but we can't do ______.
They put forward a lot of plans at the meeting, none of________ carried out in their work.