. It is clear that the whole world is passing through a social revolution in which a central _____ must be taken by scientists and technologists.

She was put under house arrest two years ago but remained a powerful ________ in last year’s election.

Whenever he meets difficulties, he always takes a positive _________ towards them.

Living in a big city has many _____, such as good schools, libraries and convenient traffic.

I quite agree with you. We are of one ______.