Alternatively, if the star were small, the life-supporting planet would have to have aclose orbit round it and also provide the perfect conditions for life forms to develop.But how would we find such a planet? At present, there is no telescope in existencethat is capable of detecting the presence of life.

　　10.Alternatively, if the star were small, the life-supporting planet would have to havea close orbit round it and also provide the perfect conditions for life forms to develop.

　　反之，如果恒星很小，维持生命的行星就要在离恒星很近的轨道上运行，而且要有极好的条件才能使生命得以发展。

　　语言点:句子结构分析:if引导虚拟语气的句子，交代相关的先决条件。

　　11.But how would we find such a planet?

　　但是，我们如何才能找到这样一颗行星呢?

　　语言点:句子结构分析:这个特殊疑问句中的such a相当于one such。

　　12.At present, there is no telescope in existence that is capable of detecting thepresence of life.

　　现在，没有一台现存的望远镜可以发现生命的存在。

　　语言点:句子结构分析:that引导定语从句。