As there is less and less coal and oil, scientists are exploring new ways of making use of ______ energy, such as sunlight, wind and water for power and fuel.
A. primary B. alternative C. instant D. unique
In our class, when the bell rang and the teacher closed his book, it was a ______ for everyone to stand up.
A. signal B. chance C. mark D. measure
Hiking by oneself can be fun and good for health. It may also be good for ______ building.
A. respect B. friendship C. reputation D. character
Some parents are just too protective. They want to ______ their kids from every kind of danger, real or imagined.
A. spot B. dismiss C. shelter D. distinguish
The loss has not yet been ______ accurately, but it is believed to be well beyond a hundred million dollars.
A. calculated B. considered C. completed D. controlled
During the war there was a serious lack of food. It was not unusual that even the wealthy families had to ______ bread for days.
A. eat up B. give away C. do without D. deal with
