问题:
A、have little or no electrical resistance.B、can be used for a long time.C、are not energy-efficient.D、can be made easily.
问题:
A、Copper.B、Liquid nitrogen.C、Clay.D、Calcium.
问题:
A、Other cities hope they can also conserve power.B、Other cities hope they can use superconducting cables soon.C、Superconductors waste less power becau...
问题:
A、With a flip of switch,electricity can be transmitted,B、Other American cities can benefit from the high-performance cables.C、Great amounts of power c...
问题:
A、"worn out".B、"ended up".C、"run out".D、"finished up".
问题:
A、worn out.B、ended up.C、run out.D、finished up.
问题:
A、poisonous gases.B、air pollution.C、water leakage.D、radiation.
问题:
A、in any stream they can find.B、in places without UV light.C、only on sand.D、only in the right conditions.
问题:
A、it has been threatened by frogs.B、it is losing its habitat.C、a disease has been killing its eggs.D、it can‘t bear the cold of winter.
问题:
A、knowledge about fatal human diseases.B、knowledge about air and water pollution.C、a chance to discover new medicines.D、an opportunity to detect poiso...
问题:
A、cause environmental change.B、cause a decline in other kinds of animals.C、be a warning signal for human beings.D、be a good sign for human beings.
问题:
A、Eating as little as possible.B、Eating no breakfast.C、Eating three regular meals a day.D、Eating no lunch.
问题:
A、He will be easily distracted.B、He will tend to lose his temper.C、He will become very talkative.D、He will feel weak.
问题:
A、drinking a glass of milk before going to bed.B、not eating too much for dinner in the evening.C、eating a big dinner in the evening.D、having some juic...
问题:
A、Fat meat.B、Rice.C、Bread.D、Juice.