Using To-Infinitives with Modals

All modal verbs, apart from ought to, require the bare infinitive after it. These modal verbs include: must, can, could, will, should and  shall, would, may, might.

• Look at this car! It must be expensive.
• Jake can swim very well.
• My parents will be mad!
• I think you ought be ashamed.
• I think you ought to be ashamed.