题目内容：

阅读下列短文，根据短文内容填空。在未给提示词的空白处仅填写1个适当的单词，在给出提示词的空白处用括号内所给词的正确形式填空。

As humans, we naturally tend to notice the bad events in life more than the good. It is because we need to keep an eye on the negative ones to keep us far away 1. dangers. If we are aware of threats around us, we are more able to switch on a defense. However, if we 2. (active) turn to focus on the positive, we can feel less stress and enjoy life more from an increasingly optimistic point. To enjoy the life in the present moment, we need to notice 3. is going right, and appreciate it. It doesn't mean that you have to pretend you're happy when you're not. On the contrary, it means that you tend to notice the things that lead to greater 4. (happy) when you have a choice.