[Grammar] should have or should had

[rajpan06]

I am learning english. I have two statemets,Which is correct of the following two statemets? and give the reason
1>They should have gone.
2>They should had gone.

 

[probus]

"Should had" is never correct. It does not exist in English grammar.

 

[MikeNewYork]

I am learning English. I have two statements. Which of the following two statements is correct? And please give the reason.
1>They should have gone.
2>They should had gone.

Please note my corrections to your question.

 

[Matthew Wai]

give the reason

The reason is that "The bare infinitive is used after modal verbs: can, should, could, might, may, etc."── quoted from http://speakspeak.com/resources/english-grammar-rules/verb-structures/verb-bare-infinitive

Not a teacher.