Which of these two is the correct option?
1. He'd better try harder, wouldn't he?
I think this is the correct way, but I am not sure. In this case, is this the long form of the sentence?
2. He'd better try harder, hadn't he?
I think this option is not correct, because the long form would have to be:
Which is the correct option?
Thank you very much in advance for your help!
The following may be checked in for instance [this Wikipedia article].
In the UK, the usual question tag after a statement using an auxiliary mirrors the auxiliary in the statement but reverses polarity:
He's tall, isn't he?
She's not daft, is she?
He can swim, can't he?
He can't swim, can he?
It's beautiful, isn't it!/?
It's not good news, is it?
She should apply for promotion, shouldn't she?
She shouldn't hide her light under a bushel, should she?
He would pass easily if he worked harder, wouldn't he?
He wouldn't pass even if he worked harder though, would he./?
'Had better/rather' do have a more cohesive nature than say 'is really' ('would better' is not in any way unary, though 'would better be [used etc]' are used: 'she'd better' etc in these constructions is always a contraction of 'she had better' etc). See these Google 5grams:
But, though had better/rather' do have a cohesive nature, the form of the tag still reflects that required by the simplex verb:
References are not easy to find; this is a repeat of the answer given on UsingEnglish.com many years ago. Note that the expanded (but archaic-sounding) expanded version is 'He had better try harder, had he not!/?' (though doubtless in the days when this sounded natural the use of the exclamation mark for the exclamatory version would have been considered improper).
Note also that the non-reversed tag question, where it is the judgement of the speaker / reliability of received wisdom rather than the clinical accuracy of the statement that is being queried (of course some tag 'questions' are really just polite attention / focusing / coercing devices: 'You'd be stupid not to consider this / agree'), is sometimes used:
He's only doing 6 hours homework a night. He'll never pass his A-Levels at this rate. He'd better try harder! ...
He'd better try harder, had he?
.........
In colloquial speech, the auxiliary verbs would and had are contracted to ’d, which can be confusing for learners of English and hence explains the OP's perplexity. How do we know whether the ’d in “He'd live in Scotland if he had the choice” is the contracted form of would or had?
In this case, it has to be would i.e. He would live in Scotland if… because of the bare infinitive “live” whereas the auxiliary had is used to construct the Past Perfect tense (had + past participle), e.g. “He had lived in Scotland for the first three years of his life.” Also, we do not use the Past Perfect in the main clause of a conditional sentence, it is only used in the conditional clause, therefore the following is ungrammatical.
He'd lived in Scotland if he had the choice. ❌
The grammatical version would be:
He would have lived [He'd have lived] in Scotland if he had had [he'd had] the choice.
Generally speaking, we use negative tags on positive clauses.
It would be better if he tried harder, wouldn't it?
Contracted form: It'd be better if…, wouldn't it?
He would do better if he tried harder, wouldn't he?
Contracted form: He'd do better if…, wouldn't he?
and positive tags on negative clauses
(i) It can't be better than mine, can it?
(ii) He wouldn't do it, would he?
The expression, had better, which is always followed by the bare infinitive (without to), is an urgent piece of advice given when something ought to/need to/must be done. In informal speech, had is often contracted to 'd or even omitted altogether: “He better try harder next time!” There's usually an implication that if the listener ignores the advice there will be an obvious consequence or negative result.
It had better work, hadn't it?
Contracted form: It'd better work, hadn't it?
He had better try harder, hadn't he?
Contracted form: He'd better…, hadn't he?
Had better is not a statement rather an imperative sentence as it is used to give advice with a warning. If it is an imperative sentence, the tag form should be ''will you?''
