用所给词的正确形式填空 。   

1.           (eat) too much is bad for your health.    

2. You should             (drink) much water when you have a fever.    

3. He is not         (feel) well because he is ill.    

4. You don't look           (good) today.  You should see a doctor.    

5. He has a headache; he should             (go) to bed early.

简述网桥的类型。