There could be life on the Mars in the future if（）
A: it supported life in the past
B: certain gases are used to cool the planet
C: the atmosphere can be heated enough to grow simple plants
D: the planet’s volcanoes become as active as they were in the past
A: it supported life in the past
B: certain gases are used to cool the planet
C: the atmosphere can be heated enough to grow simple plants
D: the planet’s volcanoes become as active as they were in the past
举一反三
- Starting with the ___ that there is life on the planet Mars, the scientist went on to develop his argument.
- The construction of "(If) simple past + (main) simple past" can be used to denote a past habit.
- 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
- A variety of gases trapped in the Earth’s atmosphere can ensure life on Earth because they are ______.
- Water is __________ (必要的) to maintain life, but only one percent of the water on the whole planet can be used for drinking.