4-1 Probability

Modal Verbs

• can
• could
• may
• might
• shall (formal)
• should
• will
• would
• must
• ought to (rare)

• They do not change forms like other verbs:
  • go ➞ goes
  • went ➞ gone
  • look ➞ looks
  • look➞ looked
• There is no do / does in the question forms:
  • Can you give me a hand?
• There is no don't / doesn't in the negative forms:
  • He shouldn't be malnourished.
• There are always followed by a base form verb. "Ought to" is the only exception as it takes "to" or "not to" before the verb:
  • We would help if we had time.
  • She mustn't do drugs!
  • We ought to get healthy.
• Some modals are used with the Perfect Infinitive to make past forms. This is more explained in Unit 12:
  • You shouldn't have done that.
  • She must have been anemic.

Modal Verbs of Probability: Present and Future