用方框中所给单词的适当形式填空，每词仅用一次 (每空一词)。

Laughter is good for you, and that's no joke! A good laugh helps you right away. When you laugh, changes in your body. For example, you take in  air than usual, which is good for your heart. A good laugh increases your heart rate. When you laugh, your brain also releases (释放) chemicals that make you feel happy. Laughing can also make you feel relaxed for up to 45 minutes.

Laughter can  reduce pain. You probably don't want to chuckle (偷笑) when you're hurt, but laughter helps the body make its own  medicine. Laughing is also great exercise! Research  that laughing 100 times is as good as riding a bike for 15 minutes.

So why don't you try laughing out loud every day?