The first question to answer iswhether a planet can actually support life. Inour won solar system, for example, Venus is fartoo hot and Mars is far too cold to support life.Only the Earth provides ideal conditions, and even here it has taken more than fourbillion years for plant and animal life to evolve.

　　4.The first question to answer is whether a planet can actually support life.

　　第一个需要解答的问题是一颗行星是否有能够维持生命的条件。

　　语言点:句子结构分析: whether a planet can actually support life充当表语从句。

　　5.In our won solar system, for example, Venus is far too hot and Mars is far too coldto support life.

　　举例来说，在我们的太阳系里，对于生命来说，金星的温度太高，而火星的温度则太低。

　　语言点:句子结构分析:too…to…结构表示“太…以致不能…。”

　　6.Only the Earth provides ideal conditions, and even here it has taken more than fourbillion years for plant and animal life to evolve.

　　只有地球提供理想的条件，而即使在这里，植物和动物的进化也用了40亿年的时间。

　　语言点:句子结构分析:take more than…to do的意思是“用了超过…的时间做。”