Besides proper diet, exercise is one of the key ___________of a healthy lifestyle.
A.categories | B.components | C.ranges | D.processes |
It will be many years ______the doctors and medical scientists can find _____ for cancer.
A.since; cures | B.when; treatments | C.before; cures | D.until; treatments |
We have to ______ everything question in detail ______ we take action.
It is clear that no use can be made ______radium _____we don’t know clearly the characteristics of it.
A.from; if | B.of; unless | C.from; unless | D.of; if |
From my point of view, the theory that ______ by the scientist is not quite scientific.
A.was risen | B.brought up | C.had been raised | D.was put forward |
The invention of steam engine greatly sped up the industrial revolution, which _____ a lot to the take-off of the world.
A.led | B.contributed | C.constructed | D.exposed |