What is the difference between:

「さて、昼 **に** しましょう。」

and

「さて、昼 **を** しましょう」。?
CC BY-SA 4.0
2021-10-31T13:17:22.567
90990
2021-11-02T15:33:27.867
2021-11-02T13:24:57.663
48518
question
grammar
What is the difference between さて、昼にしましょう and さて、昼をしましょう
...にする is a set expression indicating a choice one has/will make.

> さて、昼にしましょう

> Well, how about lunch?

* * *

There was a time when saying things like _let's do lunch_ or _let's do dinner_
were viewed as horrible California-isms. It seems they've managed to have
established themselves more broadly in English now.

But, in Japanese, saying

> 昼をしましょう

while this is technically _grammatical,_ as pointed out in the other answer,
it doesn't make much sense. (I was perhaps a bit careless in my use of the
word, _grammatical_ , previously.) 昼 here is being treated as the object of
the verb する; you don't do _afternoon_ in Japanese (even if you can make some
kind of sense of that expression in English).
CC BY-SA 4.0
2021-10-31T15:31:24.910
90991
2021-11-02T15:33:27.867
2021-11-02T15:33:27.867
4875
4875
90990
answer
昼をしましょう would mean "Let's do noon", but not in the sense of "do" meaning
"choose" as it can in English. And, "noon" is not something you can actively
do or perform. Like, you can't use it as an answer to questions like "What do
you like to do?" or "What should we do together?"

So this doesn't make sense (though, contrary to above, it _**is**_
grammatical).
CC BY-SA 4.0
2021-10-31T22:45:46.853
90995
2021-10-31T22:45:46.853
78
90990
answer
昼にする is a fixed phrase, but if you need to analyze it, I think you could see
it as a special case of `ＡをＢにする` as follows.

> （この時間を）昼（ご飯を食べる時間）にする。

By the way, コーヒーにする could be seen like that, too.

> （私が飲むものを）コーヒーにする。

昼をする makes little sense. 昼 in the sense of either “daytime” or “lunch” simply
doesn’t work well as an object of the verb する.
CC BY-SA 4.0
2021-11-01T05:13:09.847
91009
2021-11-01T05:13:09.847
43676
90990
answer