2. Should/ought to
1. We use should to give advice.
If you want to pass this class, you should study more.
If you want to lose weight, you should eat fewer calories and
exercise more.
If you have a headache, you ought to lie down and take a nap.
2. We use should to express future expectation (80% certainty)
I ordered the book from Amazon last week. It should arrive any day
now.
You reviewed the lesson 5 times, so you ought to understand it by
now.
The teacher is still talking; however, class should end any minute so
just wait for me.
3. Should have/ought to have
1. We use should have to give hindsight advice.
You failed the test. You should have studied more.
Holly broke her toe. She ought to have been more careful.
Lan wasn’t feeling well yesterday but she came to class anyway. Now
her condition is worse. She should have stayed home and rested.
2. We use should have to express past expectation.
I ordered the book from Amazon three weeks ago. It should have
arrived already!
You studied for the test and you understood the material, so you
should have passed the test. We will have to wait to see your grade.
Paola has been waiting for Van for the past 2 hours. Paola doesn’t
understand it; Van ought to have arrived a long time ago!
4. Must
1. We use must to express obligation or a requirement.
Students must take the Compass Test at the end of the term in order to pass to the
next level.
If you get pulled over by the police, you must give them your driver’s license and
proof of insurance.
2. We use must to express 95% certainty (logical conclusion to some information or
evidence).
Arkan isn’t in class now. He must be at home sleeping.
Holly told us to read 200 pages by tomorrow. She must be joking.
You studied so hard for this test. You must know the answer to this question!