I have noticed that sometimes some people say (or only write?):

I watched two movies. The first I didn't like, but the second was very good. ( I didn't like the first, but...)

Claire Bowie, who had been working the night shift at the airfield since 1954, logged the request at 4:32 am. The time of landing he noted as 4:49 am; he recorded the pilot name as Dwight Renfield [...] ( He noted the time of landing as 4:49 am...)

What is it? Formal, informal, only found in written English, etc? Is it only idiomatic in certain structures, rather than in most cases? ("There was a banana and an apple. The apple I ate at once, but I kept the banana" <--- puzzled)

Thanks. Emotion: smile
Hi, Kooyeen. I think you [unwittingly] exposed the key. Both your examples begin with subject - verb. To repeat the same format would sound dull. I think it's a matter of style: Introductory sentence (S - V); Wham! (Something significant! - And something which sets up an anticipatory pattern.)
Try reading your examples both ways, and notice how drab the normal way sounds. It just puts you to sleep.

Anyway, that's my off-the-wall reaction.

Best wishes, - A.
Teachers: We supply a list of EFL job vacancies
Fronting the direct object is much more common in conversation than most people realize. It's definitely not restricted to writing.
I think people just start a sentence thinking the first noun phrase is going to be the subject, and then suddenly a different verb comes to mind than they expected, so they end up throwing in a subject for that verb and the first noun phrase that came out ends up being the object. (This is the thinking-on-the-fly theory.)
Or they may deliberately put the object first because it has more importance for them -- they're going to contrast it with something else, for example. X, but not Y. X now, Y later. That sort of thing. (All of your examples contain this feature.) (This is the contrast theory.)

The dirty dishes I'll do now, but [I'll do the laundry later. / the laundry I'll do later / the laundry can wait].
Thanksgiving I can just about handle, but Christmas drives me nuts.
I've got to get the main points of this essay down on paper; the introduction I can write later.
Thanks, I see.
I have never "heard" anything like that, I only have read it, so I don't know about the intonation, if there are any pauses, etc. I'll try to remember this thread in case I "hear" something like that, but I won't attempt to reproduce such structures for now. Emotion: smile
The adverbs (or the last words) in each clause usually have almost identical intonation, from high to low. A single syllable word like "now" would have the hi-lo across the syllable. For a two syllable word with the accent on the first syllable, like "later," the first syllable would be high and strong and the second would be low and nearly inaudible. In Kissinger's "The illegal we do immediately; the unconstitutional takes a little longer," the "im" is mid range in pitch and volume, the "med" is strong and high, and the last three syllables are almost suppressed. But the hi-lo endings of the two clauses are ballanced. If a two-syllable reverse accent is involved (a-non - hey, it begins with "a"), the first syllable is mid range and the last syllable carries the full hi-lo.

An exception would be if the speaker has been debating which to do first, and wishes to indicate that he's finally made up his mind. The hi-lo would be transferred from the adverb to the chosen activity. "The dish-es I'll do now; the laundry I'll do later." The "now" would be flat. The second clause would be normal, or possibly with a lesser hi-lo on the "laundry".

I'd say there's always at least a slight pause between the clauses, and of course it may be increased for dramatic effect.

- A.
Students: We have free audio pronunciation exercises.