1.  On the other hand, boundaries are significant because they are used by human to keep up their own fields, both geographically and mentally.

2.  We human indeed use them to improve our living standard, but on the other hand, we are becoming lazier, more reliable than we used to be.

3.  In my view, human should use the advanced the artificial intelligence properly and wisely in bringing benefit to mankind.

4.  Another aim, is to consider how humans can use the space science exploration, and the exploration of the actual purpose is in the exploration of the gradual development out.

5.  Another problem worth considering is that the arguer fails to show the relation between simple tools and the conclusion humans use these tools for hunting.

6.  Long long ago, humans can only use fire and water to bring convenience to their lives.

7.  Besides, the simple tones such as stone knives might be used by humans to protect themselves from the fierce animals' attack.

8.  It is reasonable that early humans used stone knives to keep the beast away.

9.  Humans might use them to make a mark, make a fire or do some other things.

10.  Although human used them for hunting, the conclusion is not persuasive.