Question

they had a good time last night ,__?

Answer 1

They had a good time last night, didn't they?
此句中，had是实意动词，所以变成反问疑问句时，要用助动词didn't；
如果had在句中充当助动词的话，变成反问疑问句时就用hadn't，如：
She had gone there, hadn't she?

Answer 2

they had a good time last night ,_right_?

Answer 3

they had a good time last night ,right？

Answer 4

had not they？