题目内容：

    While you eat, you use them to help cut up food. When you smile, you show them off to look your best. Sep. 21 will be the 28th National Teeth Care Day in China. It’s the perfect time for you to learn some tips on how to protect your teeth.

First of all, we need to pick a good toothbrush. Softness is the key. Brushes with hard bristles (刷毛) can hurt your teeth and gums (牙龈). Choose one with soft bristles and rounded ends. Also, it is easy for you to reach all your teeth with a brush with a small head, since they can push into the small spaces of your mouth.

Next you need to learn the correct way to brush our teeth. Doctors around the world recommend the Bass brushing technique (贝氏刷牙法).The method advises you to brush your teeth along the gum line at a 45-degree angle (角度) with very small back-and-forth vibrating motions (颤动). Bad things usually hang out where the gums and teeth meet. You can clean the area well and prevent tooth and gum disease with this method.

After a good brush, you need to go on to floss (用牙线清理) your teeth. Put dental floss into the space between two teeth and use a careful back-and-forth motion. It helps get food out of the spaces. But don’t move the floss too hard, or it may hurt your gums.

Tips on how to protect your teeth
Before brushing	Picking a good toothbrush with soft bristles is the most 1. or your teeth and gum can be hurt.
Choosing a toothbrush with a small rounded head also matters a lot because it can easily reach all your teeth without any 2..
While brushing	The Bass brushing technique is highly recommended.
This method 3. brushing your teeth along the gum line at a 45-degree angle with very small back-and-forth vibrating motions, which can clean the area well.
After brushing	For a 4. clean, you’d better to floss your teeth to get food out of the spaces between two teeth.
Remember to move the floss gently to 5. hurting your gums.