题目内容：

阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

My dear grandson, your mother tells me that you 1.(start) smoking some time ago and now you are finding it difficult 2.(give) it up. By the way, did you know that this is 3. you become addicted in three different ways?

Firstly, you can become physically addicted to nicotine, 4. is one of the hundreds of harmful chemicals in 5.(cigarette). This means that 6.(accustom) to having nicotine in it, you feel good. But when the drug leaves your body, you get withdrawal symptoms. I remember 7.(feel) bad-tempered and sometimes even more pain.

Secondly, you become addicted 8. habit. As you know, if you do the same thing over and over again, you begin to do it automatically. Lastly, you can become 9.(mental) addicted. I believed I was 10.(happy) and more relaxed after having a cigarette, so I began to think that I could only feel good when I smoked. I was addicted in all three ways, so it was very difficult to quit. But I did finally manage.