Perfect Infinitives

Perfect infinitives are forms like have sent, have received, have worked and have ordered. They are mainly used after modal auxiliary verbs like would, should and could.

• You should have informed me earlier.
• You could have arrived earlier.
• I would have invited him.
• You shouldn’t have called him a liar.
• She shouldn’t have ignored the doctor’s advice.

These expressions are mainly used to criticize people for doing or not doing things.

The perfect infinitive is also used in third conditional sentences. The third conditional is used to talk about hypothetical situations.

Study the examples given below.

• I would have invited her if she had been nice to me.
• We would have been in real trouble if I had lost my job.
• I could have won the first rank if I had studied harder.

You can learn more about perfect infinitives here.