Building a city can be a disaster for the environment.
新建一个城市对于环境来说可能是一场灾难。
At the moment, he is a bit worried about his English.
就在那时候,他有点担心他的英语。
Alternatively, if the star were small, the life-supporting planet would have to have a close orbit round it and also provide the perfect conditions for life forms to develop.