do do 表强调Do be careful. Do be sensible. It does make it impossible.will do,shall do. 表预料判断。I will do it. We shall do it.can do表能力I can do it.may do表许可You may go now.needn't do表没必要You needn't explain.must do主观必须 I must work hard.had better do威胁性应该You had better...
