Present Conditional Tense

The present conditional tense is used to speculate about things at present or in the future that are possible. This is used specifically when something is not going to happen.

He would walk with us (but he cannot). He would travel by car (but he doesn’t have a driving license)

Neutral/Positive: I would walk
Negative: I would not walk
Question: Would you walk?
Negative Question: Would he not walk? (wouldn’t he walk?)

Should is similar to would, but is mainly used to express a correct choice.
I should go to the gym (it is good for me)
He should wear a safety helmet (to protect his head when he rides a bike)
We should walk more quickly (we are late)

Should is very similar to ought to (we ought to walk more quickly).

Could (can) and might (may) are other conditionals that are also used to speculate about things in the present or future. Could means that something is possible in theory, and Might indicates true possibility but with uncertainty.
I could go to London tomorrow (indicates that you have free time to go to London tomorrow ).
I might go to London tomorrow (indicates that there is a possibility you will go to London tomorrow).

Could also expresses the permission to do something and the ability to do something.
He could ride on his bike once his foot had healed.
My mother gave me permission. I could go to the ball!

Past Conditional Tense

Neutral/Positive: I would have walked
Neutral: I would have walked
Negative: I would not have walked (I’d not have walked)
Question: Would you have walked?
Negative Question: Would you not have walked? (wouldn’t you have walked?)

Perfect Conditional Tense

Perfect conditional tense is used to speculate about situations in the past where we may have done something, or that something was possible in theory, but did not happen.

The perfect conditional is formed by using would + have + past (perfect infinitive) participle.

I would have gone to school (but I was ill)
I would have listened (but I was busy)
She would have known (but I did not tell her)
She would say yes (present – a certainty that she is going to say yes if I ask here)
She would have said yes.

Should, Might and Could are similar to each other. Might and Could are used for speculation in the past over an event that had a possibility of happening but didn’t.

I might/could have gone to school (but I was ill)
I might/could have listened (but I was busy)
She might/could have known (But I did not tell her)
I could have died (but the doctor saved me)

Should indicates something that would have been better to have been done but wasn’t. Often used to express regret

I should have gone to the party (because it would have been fun)
I should have exercised yesterday (because I am getting fat)
I should have accepted the agreement
I should not have accepted the agreement

May is similar to Might, but we are unsure of whether the action or event happened or not.

She may have walked to school (maybe she did, maybe she didn’t)
Mars may have been home to aliens millions of years ago.

Test your knowledge and take the test on Conditional Tense!

More Grammar Rules:

Active/Passive Voices
Direct/Indirect Objects

More Grammar Quizzes:

Active/Passive Voices
Direct/Indirect Objects