you must go to the hospital.

you had to go to the hospital.

you would go to the hospital.

you could go to the hospital.

you can see the birds clearly.

you could see the birds clearly.

you would see the birds clearly.

you might see the birds clearly.

you got angry.

you have gotten angry.

you get angry.

you are getting angry.

teachers were always happy.

teachers are always happy.

teachers will always be happy.

teachers would be always happy.

I walk to school.

I walked to school.

I am walking to school.

I was walking to school.

you could get tired.

you would get tired.

you get tired.

you had gotten tired.

you get four.

you got four.

you are getting four.

you had gotten four.

you should be quiet.

you would be quiet.

you could be quiet.

you might be quiet.

wanted / had

have wanted / have had

want / have

would want / would have