Can, Might, Should

"Might" is most commonly used to express possibility. It is also often used in conditional sentences. English speakers can also use "might" to make suggestions or requests, although this is less common in American English.

Examples:

• Your purse might be in the living room. possibility
• If I didn't have to work, I might go with you. conditional
• You might visit the botanical gardens during your visit. suggestion
• Might I borrow your pen? request

Using "Might" in Present, Past, and Future

Most modal verbs behave quite irregularly in the past and the future. Study the chart below to learn how "might" behaves in different contexts.

Modal Use	Positive Forms 1. = Present   2. = Past   3. = Future	Negative Forms 1. = Present   2. = Past   3. = Future	You can also use:
might possibility	1. She might be on the bus. I think her car is having problems. 2. She might have taken the bus. I'm not sure how she got to work. 3. She might take the bus to get home. I don't think Bill will be able to give her a ride.	1. She might not be on the bus. She might be walking home. 2. She might not have taken the bus. She might have walked home. 3. She might not take the bus. She might get a ride from Bill.	could, may
might conditional of may	1. If I entered the contest, I might actually win. 2. If I had entered the contest, I might actually have won. 3. If I entered the contest tomorrow, I might actually win. Unfortunately, I can't enter it.	1. Even if I entered the contest, I might not win. 2. Even if I had entered the contest, I might not have won. 3. Even if I entered the contest tomorrow, I might not win.
might suggestion	1. NO PRESENT FORM 2. You might have tried the cheese cake. 3. You might try the cheesecake.	1. NO PRESENT FORM 2. PAST FORM UNCOMMON 3. You might not want to eat the cheese cake. It's very calorific.	could
might request (British form)	Might I have something to drink? Might I borrow the stapler? Requests usually refer to the near future.	NEGATIVE FORMS UNCOMMON	could, may, can

REMEMBER: "Might not" vs. "Could not"  "Might not" suggests you do not know if something happens. "Could not" suggests that it is impossible for something to happen. Examples: Jack might not have the key. Maybe he does not have the key. Jack could not have the key. It is impossible that he has the key.

"Can" is one of the most commonly used modal verbs in English. It can be used to express ability or opportunity, to request or offer permission, and to show possibility or impossibility.

Examples:

• I can ride a horse. ability
• We can stay with my brother when we are in Paris. opportunity
• She cannot stay out after 10 PM. permission
• Can you hand me the stapler? request
• Any child can grow up to be president. possibility

Using "Can" in Present, Past, and Future

Most modal verbs behave quite irregularly in the past and the future. Study the chart below to learn how "can" behaves in different contexts.

Modal Use	Positive Forms 1. = Present   2. = Past   3. = Future	Negative Forms 1. = Present   2. = Past   3. = Future	You can also use:
can general ability	1. I can speak Chinese. 2. SHIFT TO "COULD" I could speak Chinese when I was a kid. 3. SHIFT TO "BE ABLE TO" I will be able to speak Chinese by the time I finish my course.	1. I can't speak Swahili. 2. SHIFT TO "COULD" I couldn't speak Swahili. 3. SHIFT TO "BE ABLE TO" I won't be able to speak Swahili.	be able to
can ability during a specific event	1. With a burst of adrenaline, people can pick up cars. 2. SHIFT TO "BE ABLE TO" With a sudden burst of adrenaline, he was able to lift the car off the child's leg. 3. SHIFT TO "BE ABLE TO" With a sudden burst of adrenaline, he will be able to lift the car.	1. Even with a burst of adrenaline, people can't pick up something that heavy. 2. SHIFT TO "BE ABLE TO" Even the weight lifter, couldn't lift the car off the child's leg. 3. SHIFT TO "BE ABLE TO" Even three men working together won't be able to lift the car.	be able to
can opportunity	1. I have some free time. I can help her now. 2. SHIFT TO "BE ABLE TO" I had some free time yesterday. I was able to help her at that time. 3. I'll have some free time tomorrow. I can help her then.	1. I don't have any time. I can't help her  now. 2. SHIFT TO "BE ABLE TO" I didn't have time yesterday. I wasn't able to help her at that time. 3. I won't have any time later. I can't help her then.	be able to
can permission	1. I can drive Susan's car when she is out of town. 2. SHIFT TO "BE ALLOWED TO " I was allowed to drive Susan's car while she was out of town last week. 3. I can drive Susan's car while she is out of town next week.	1. I can't drive Susan's car when she is out of town. 2. SHIFT TO "BE ALLOWED TO " I wasn't allowed to drive Susan's car while she was out of town last week. 3. I can't drive Susan's car while she is out of town next week.	may
can request	Can I have a glass of water? Can you give me a lift to school? Requests usually refer to the near future.	Can't I have a glass of water? Can't you give me a lift to school? Requests usually refer to the near future.	could, may
can possibility, impossibility	Anyone can become rich and famous if they know the right people. Learning a language can be a real challenge. This use is usually a generalization or a supposition.	It can't cost more than a dollar or two. You can't be 45! I thought you were about 18 years old. This use is usually a generalization or a supposition.	could

"Should" is most commonly used to make recommendations or give advice. It can also be used to express obligation as well as expectation.

Examples:

• When you go to Berlin, you should visit the palaces in Potsdam. recommendation
• You should focus more on your family and less on work. advice
• I really should be in the office by 7:00 AM. obligation
• By now, they should already be in Dubai. expectation

Using "Should" in Present, Past, and Future

Most modal verbs behave quite irregularly in the past and the future. Study the chart below to learn how "should" behaves in different contexts.

Modal Use	Positive Forms 1. = Present   2. = Past   3. = Future	Negative Forms 1. = Present   2. = Past   3. = Future	You can also use:
should recommendation, advisability	1. People with high cholesterol should eat low-fat foods. 2. Frank should have eaten low-fat foods. That might have prevented his heart attack. 3. You really should start eating better.	1. Sarah shouldn't smoke so much. It's not good for her health. 2. Sarah shouldn't have smoked so much. That's what caused her health problems. 3. Sarah shouldn't smoke when she visits Martha next week. Martha hates when people smoke in her house.	ought to
should obligation	I should be at work before 9:00. We should return the video before the video rental store closes. "Should" can also express something between recommendation and obligation. "Be supposed to" expresses a similar idea and can easily be used in the past or in negative forms.	NO NEGATIVE FORMS	be supposed to
should expectation	1. Susan should be in New York by now.  2. Susan should have arrived in New York last week. Let's call her and see what she is up to. 3. Susan should be in New York by next week. Her new job starts on Monday.	1. Susan shouldn't be in New York yet. 2. Susan shouldn't have arrived in New York until yesterday. 3. Susan shouldn't arrive in New York until next week.	ought to, be supposed to