1. 助动词 have / has / had + 过去分词。构成完成时。

have - I / we / you / they

They have finished the work.

They haven’t finished the work.

‘Have they finished the work?’ ‘Yes, they have.’

has - he / she

He has finished the work.

He hasn’t finished the work.

‘Has he finished the work?’ ‘Yes, he has.’

had

She had finished the work when I arrived.

She hadn’t finished the work when I arrived.

‘Had she finished the work when you arrived?’ ‘Yes, she had.’

2. 与 作实义动词时的区别。

实义动词 + 名词

He has a football.

Does he have a football?

助动词 + 动词

He has played football today.

Has he played football today?