have to, ought to ,must ,have to

Must個意念係係最strong ge,係表達自己的意見,而must只可以當做present tense or future tense,而唔可以當作past tense ,佢同have to差唔多,當然 have to意念冇must 咁強
e.g.1.This film is very good,you must watch it!
2.IT was almost midnight.Must i phone to Mary now??


Have to(past tense:had to)(negative:doesn't have to,don't have to,didn"t have to)
e.g.1.The typhoo signal is hoisted.We don't have to go to school.
2.It was 10 o' clock.You had to go to bed now.

Must 所講ge野一定係指定要咁樣做,have to 所講ge野唔一定要做
e.g.1.Tomorrow is the holiday.You don't have to get up early.(你可以唔駛咁早起身,但你亦可以有權早d 起身,so 用have to)
2.Tomorrow is the public holiday.You must not go to school.
(睇日係public holiday,你一定唔可以番學,因為冇人會開門俾你)


Ought to=should.(negative:ought not to)通常有think出現,意念冇must& have to 咁strong
e.g. 1.I think you ought to go bed now.
2.Ought I to eat less to keep fit?

希望可以幫到你,不過唔知有冇錯(我諗應該都啱)

首先,ought to = should(意思是:應該)
e.g It is late I ought to go bed now.
It is late you ought not to(ought'nt to) watch TV now.
Ought I to turn on the fan?
Must(比意見）
e.g I must stop smoking.

Have to(責任）
e.g Cotholics(天主教徒)have to go chunch on Sunday.

Must的Past tense係Had to
Have to的Past tense都係Had to