Should I use "had had", "did have", or "had"?

Question

When using "double words" such as "had had", is this grammatically correct, and is there a better way to say the sentence?

Which of these is better?

1. He had had a drink
2. He did have a drink
3. He had a drink

Answer 1

None of these are "better" or "worse", they just mean different things. Let's examine them in reverse order.

3. He had a drink.

This is the simple past tense. It means that at some point in the past, he drank something.

2. He did have a drink.

This looks like the emphatic do, in the past tense. It means the same thing as #3 (at some point in the past, he drank something) but the addition of do adds emphasis. You might use it in an exchange like

"I know he didn't drink anything."
"You're wrong, he did have a drink."

1. He had had a drink.

This is the past perfect tense. It means that he drank something before another time in the past. You might use it like "He thought about driving home (so the thinking was in the past) but he had had a drink (having a drink was in the past, before the thinking)."

It looks confusing, because of the "had had", but the first had is just the auxiliary verb of the past perfect (as in had eaten, had slept, had thought) and the second had is the past participle of to have (just like eaten, slept, and thought are the past participles of eat, sleep, and think).

Answer 2

This happens because of a coincidence in English.

Many English verb phrases are formed by an auxiliary and a main verb. The auxiliary gives the tense and and aspect, and the main verb gives the meaning.

He is [auxiliary] eating [main verb]

He has [auxiliary] written [main verb] a book.

Now it is possible to form a sentence in which both the main verb and the auxiliary are forms of the verb "have".

He has had a biscuit.

This is a perfect tense, and it uses the past participle "had".

Now it is a coincidence that the past tense form of "have" is also "had"! (In most languages with participles, the participles are different from the past tense - English is a bit weird)

If you for the past perfect you get:

He had had a biscuit.

It looks odd but the two words are the same, but functioning differently. The first is a past tense auxiliary and the second is a past participle main verb.

You can get the same thing with "do"

"I do up my shoelaces" (normal)

You never do up your shoelaces.

You're wrong! I do do up my shoelaces, every day!

And with other words that happen to have the same form. For example the verb "bat"=hit and the noun bat=flying mammal.

He bats bats with a cricket bat.

We would often try to avoid these double words, but sometimes they are essential to the meaning that we want to give.