用should 或shouldn't 填空。
1. All of us              study hard and learn English well.
2. As a student, you              eat in class.
3. You              speak to your parents like this ,you must be polite (有礼貌)
4. You              eat less and take more exercise if want ot be healthier and stronger.
5. My mother is very after work, I              do some housework for her.