According to the report, some well-known scientists believe that there is not enough oxygen on Mars to __________ human life.()
A: sustain
B: retain
C: remain
D: entertain
A: sustain
B: retain
C: remain
D: entertain
举一反三
- According to some scientists, global warming the survival of the whole human race.
- Some that the distant planet could sustain life. But so far there is no solid evidence for any signs of life there.
- Some scientists think there may have been life on the Mars in the past because （） A: there is no life there now B: there is a large amount of water at the poles C: the Mars may be able to support life in the future D: conditions may have been similar to those on the Earth
- He built a pair of wings of a size suitable to _______ his own weight, and made use of gravity as his motor. A: entertain B: retain C: obtain D: sustain
- According to the passage, dogs and cats ______ . A: as well as human beings cannot see some colours B: have fewer cones than human beings C: have less rods than human beings D: can see colours as well as human beings