题目内容
（请给出正确答案）
[主观题]
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
如搜索结果不匹配，请 联系老师 获取答案
