题目内容：

阅读下面材料，在空白处填入适当的内容（不多于3个单词）或括号内单词的正确形式。

Not all memories are sweet. Some people spend all their lives trying to forget bad experiences.

Now American researchers think they are close to developing a pill, ___1.___ will help people forget bad memories. The pill is designed ___2._ (take) immediately after a frightening experience. They hope it might reduce, or ___3.__ (possible) erase (抹去) the effect of painful memories.

In November, experts tested a drug on people in the U.S. and France. The drug stops the body from __4.___ (release) chemicals that fix memories in the brain. So far, the research __5.___ (suggest) that only the emotional effects of memories may be reduced, not that memories are wiped out. They are not sure to the degree people’s memories are affected.

The research has caused a great deal of ___6.__ (argue). Some think it is ___7.__ bad idea, while others support it. Supporters say it could lead to pills which prevent or treat soldiers’ troubling memories after war. They say that there are many people who suffer from terrible memories. ___8.___, those who are ___9.___ the research say that maybe the pills can change people’s memories and changing memories is very __10.___ (danger) because memories give us our identity.