Bad breath(呼吸) is a big problem. It may make people feel bad if we have it when we are talking to them. 

Why do we have bad breath? If we don't brush our teeth, bacteria (细菌) will live between our teeth and make our breath smell bad. Food like onions can also make us have bad breath. Smoking is an important reason(原因) for bad breath.

How can we stop bad breath? Some people say that mouthwash (漱口剂) can make bad breath go away, but it's not true. Mouthwash only stops bad breath for a short time. Some people also say that brushing teeth can stop bad breath. The fact is that most people only brush teeth for 30-45 seconds（秒）. It doesn't work at all. We should brush our teeth for about 2 minutes twice a day.

If we don't want to have bad breath, be sure to take good care of our teeth.