Can modal fe’li ish-harakatning bajarilish imkoniyati yoki qobiliyatini bildiradi. Can

Can’t + oddiy shakldagi fe’l esa biror narsani bo’lishi mumkin emas, imkonsiz, ilojsiz deb hisoblanganda ishlatiladi: You have only just had dinner. You can’t be hungry already.
Could modal fe’lidan keyin oddiy shakldagi fe’l kelgan bo’lsa o’tgan zamondagi ish-harakatning qobiliyati yoki imkoniyatini bajarilgan yoki bajarilmaganligini bildiradi: Gapning mazmuniga qarab, bajarilgan bo’lsa, uddalay oldi, bajarilmagan bo’lsa, uddalay olardi deb tarjima qilinadi, ammo uning ekvivalenti was, were able to faqat uddalay oldi deb tarjima qilinadi va sodir bo’lgan ish-harakatga nisbatan ishlatiladi.
He could help his motherland but he didn’t.
He could help his motherland. He freed the country. = He was able to help his motherland. He freed the country.
My boss could speak five foreign languages.
Your brother could help you. Why didn’t you phone him?
This student could translate the article without my help.
Could + oddiy shakldagi fe’l kamdan-kam hollarda o’tgan zamonni emas, kelasi zamonga tegishli ehtimollikni ham bildiradi: There could be another rise in the price of petrol soon.
Could + Perfect bo’lsa, o’tgan zamondagi ish-harakatning bajarilish imkoniyati, qobiliyati bo’lganligi, ammo bajarilmaganini yoki biror ish-harakatning sodir bo’lish ehtimoli bo’lganligi, ammo sodir bo’lmaganini bildiradi:
We could have gone to the cinema last night but we decided to stay at home.
He was lucky when he fell off the ladder. He could have hurt his leg. ---------------------------------------------
MUST modal fe’li (shart, zarur, kerak, lozim) ish-harakatning ma’lum sharoitda bajarilishi zaruriyatini hamda buyruq yoki maslahatni ifodalaydi.
Must dan keyin oddiy shakldagi fe’l kelgandakelasi yoki hozirgi zamonni bildiradi:
We must go now. I must visit my parents tomorrow.
You must learn this rule at once. (buyruq)
He must consult a doctor if he is ill. (maslahat)