English

Should / would have + past participle
Should can be used with a perfect infinitive (have + past participle) to talk about past events which did not happen, or which may or may not have happened.

Should สามารถนำมาใช้กับ perfect infinitive (have + past participle) พูดเกี่ยวกับเหตุการณ์ในอดีตซึ่งไม่เกิดขึ้น,หรือซึ่งอาจจะหรืออาจจะไม่เกิดขึ้น.
I should have posted the letter this morning, but I clean forgot. (Here we are talking about a past event which did not happen.)
She should have arrived now. (Here we are talking about the possibility of an event actually taking place.)
You should have written. I was getting worried. (The person didn’t write.)

"I should have gone with you."
"I should have studied more for my test."
"I should have read the directions before starting."
"I should have eaten breakfast this morning."
"I should have listened to your advice."
"I should have married her when I had the chance."

Should not + have + Past Participle

Ought not to + have + Past Participle

มีความหมายว่า ไม่ควรจะกระทำสิ่งหนึ่งสิ่งใดในอดีต แต่ได้กระทำไปแล้ว เช่น

- The party was boring. I shouldn’t have gone there.

- They oughtn’t to have been absent from school yesterday.