To show how sure we are about something we use modal verbs. If we are very sure it is true: She works every night, so she must be very determined. If we are sure it is not true: He can’t be lazy; he finished three projects. If it is possible but we are not sure: They might / may / could be late. For the past: must have + past participle: He must have studied hard. Character adjectives: ambitious, determined, generous, modest, reliable, stubborn, curious, creative. Successful people usually have clear goals, work hard and care about others, but success looks different for everyone: one person becomes a scientist and another a helper in the community. In an “odd one out” task find the word that does not belong and give the reason.
Worked examples
Look at his certificates. He must be a very hard-working student. She can’t be shy – she gave a speech to the whole school!
Odd one out: generous, modest, lazy, reliable. Lazy is the odd one because the others are positive qualities.
Class activity
“Detective”: the teacher gives three clues about a person (bag, hands, clothes) and students make guesses with must / might / can’t.
Practice
1
Complete: He has won five science contests. He ___ be very clever. (must / can’t)
must
2
Odd one out: curious, creative, bored, ambitious. Why?
bored – the other words describe positive qualities that help to succeed.
3
Make a deduction about the past: Her eyes are red. (cry)
She must have cried.
4
Why is “must be” a stronger guess than “might be”?
Because must shows we have good evidence and are almost sure; might shows only a small possibility.