根据短文内容和首字母的提示，把所缺单词填写在短文后面的横线上。
Robot s__1__ are not just trying to make robots look like people. For example, there are already
robots w__2__ in factories.These robots look more like huge arms.They do simple jobs over and over
again.People would not like to do such jobs and would get bored. But robots will never get bored. In
the future, there will be more robots e__3__, and humans will have l__4__ work to do. New robots
will have many different shapes. Some will look like humans, and others might look like snakes. After
an earthquake, a snake robot could help look for people under b__5__. That may not seem possible
now, but computers, space rockets and even electric toothbrushes seemed i__6__ a hundred years
ago.We never know what will happene in the future.
