Please choose the correct ending to complete the given sentence: Health: [header] How to remove tartar [title] Brush your teeth at least twice a day. [step] Since tartar is caused by plaque buildup, it's important to remove plaque by brushing your teeth for about 2 minutes at least twice every day. [substeps] Wait about 30 minutes after you eat before you brush, since eating can soften the enamel on your teeth.

Ending1: Brush your teeth hard, especially around the gums and the backs of your teeth, once a day. These areas are probably the easiest to see, but some people might mistake this as a sign your toothbrush is putting too much pressure on them. Ending2: [title] Use a glass of water for daily brushing. [step] Although tartar on your teeth can be a source of excessive plaque, using a glass of water before you brush helps the plaque build up and helps remove tartar. Ending3: With a bowl of warm water and toothbrush, gently scrub your teeth with a soft toothbrush. Keep floss and rinse your mouth after flossing. Ending4: If you brush too soon after eating, you can remove enamel, which will weaken your teeth over time. [title] Brush the front, back, and chewing surface of your teeth.

Answer format: ending1/ending2/ending3/ending4