It will rain tomorrow.
Certain
I hurt my foot while running, what should I do?
You should [go to the doctor]!
What is a modal we can use to express that we are certain about something?
Will / Must
If your kitty is hungry, you could feed it a watermelon.
What's wrong with this? What could I do instead?
Watermelons are too big and cats can't open them!
What will you do if it is sunny tomorrow?
If it is sunny tomorrow, I will go to the park.
I might ace my exams.
Possible
I have an exam tomorrow and I'm not prepared, what can I do?
You can [have a cram session tonight]!
What is a modal we can use to give advice to people?
Should, could, would, etc.
If you want to get a job as a police officer, you must run into the police station and find the manager.
What's wrong with this? What could I do instead?
If you run into the police station, they might think you are a criminal and arrest you!
Instead, you must send your resume in to their office.
What might you do if you found a million dollars?
If I found a million dollars, I might buy a house!
I must feed the dog.
Certain
I want to earn a billion dollars, what must I do?
You must [work really hard and get lucky]!
What is a modal we can use to ask permission?
May, can.
If someone steals your wallet, you might find it by searching everyone's pockets.
What's wrong with this? What could I do instead?
If you try to search everyone's pockets, they will all think you are the thief!
Instead, contacting the police might solve the problem!
What could you do if you had a personal airplane?
If I had a personal airplane, I could fly all over the world!
Tomorrow should be a fun day.
Probable
What might be a good way to make more friends?
A good way to make more friends would be to [attend more social events]!
What is a modal we can use to express obligation?
Must
If the boy wants to score at the top of his class, he may try cheating on all the tests!
What's wrong with this? What could I do instead?
If he cheats, he will probably get in big trouble!
Instead, he may simply try to study more.
What could you do to make your parents happy?
To get make my parents happy, I could be a good boy!
He could get a good job in the future.
Possible
What's one way I could solve my problem of getting older and older?
You could solve this problem by [exercising more and eating right]!
What is a modal we can use to express a conditional mood?
All of them!
If you want to get over this wall, you should get a trebuchet.
What's wrong with this? What could I do instead?
If you use a trebuchet, you would surely die because it would throw you way too far! Instead, you should [use a ladder]!
What should you do if there is a fire in the building?
If there is a fire in the building, I should calmly and quickly find the exit!