为自己加油

Try to translate the following into Chinese .5.But without fire, life on earth was very difficult. Food had to be eaten raw; house could not be kept warm. Tools had to be of stone, because there was no fire for working metals.

但是，没有火，人世间生活是非常困难的。食物只能生吃，房子无法保暖；工具只有石制的，因为没有火，金属无法熔炼。