13. You had to do it well, didn't you?(陈述部分的谓语包含have to, has to, had to时，疑问部分要用do 的适当形式。)

12．We usually have breakfast at seven, don't we?(当have不作"有"解而用作行为动词时，简略问句用do 适当形式)

11. He used to get up early, didn't he/ usedn't he?(当陈述句含有used to 时，简略问句用did,也可重复used.)

10. The boys mustn't play with fire, may they?(当must表示"禁止"时，反意问句要用may.)

9． You must have seen the film "Shaolin Brothers", haven't you?(当must+不定式的完成式表示对过去事情的推测时，用have。)

8． It must be Xiao Wang, isn't it?(must be在这里表示推测，要用be 的适当形式)

7． We must study all the subjects well, needn't we?(must在这里不表示"必须"，只表示"有必要"， 所以不重复must, 要用need.)

6． Let us go for a walk, will you?/won't you?(Let us 不包括听话者，而是向听话者提出建议或要求。)

5． Let's go to the station shall we?(Let's 包括听话者，所以用shall we?)

4． Don't forget to write a letter to me, will you?(在否定祈使句中，只用will you?)