〜も details
as many as; as much as — a quantity the speaker presents as beyond what was expected
昨日、病院で三時間も待たされたんだよ。
kinou, byouin de sanjikan mo matasareta n da yo.
They kept me waiting three whole hours at the hospital yesterday. casual
この店、近いのにまだ一度も入ったことないんだよね。
kono mise, chikai noni mada ichido mo haitta koto nai n da yo ne.
It's close by, and yet I've never once been in. casual
Examples
as many as — the amount is stated as surprisingly large
昨日、病院で三時間も待たされたんだよ。
kinou, byouin de sanjikan mo matasareta n da yo.
They kept me waiting three whole hours at the hospital yesterday. casual
この展示会には、一日で二千人も集まったそうです。
kono tenjikai ni wa, ichinichi de nisennin mo atsumatta sou desu.
I hear as many as two thousand people came to this exhibition in a single day. neutral
not even one — 一〜も with a negative predicate denies the set outright, rather than reporting a shortfall
この店、近いのにまだ一度も入ったことないんだよね。
kono mise, chikai noni mada ichido mo haitta koto nai n da yo ne.
It's close by, and yet I've never once been in. casual
その件につきましては、ご報告を一件も受けておりません。
sono ken ni tsukimashite wa, go houkoku o ikken mo ukete orimasen.
We have not received a single report regarding that matter. formal
Formation
{Q}もattaches to number + counter
Notes
一回も all need ない — while the measure counters stay free
(一時間も待った, 一年も経った).
Related patterns
Similar
さえ pushes a single item past expectation by itself and reads more emphatic and more written (名前さえ書かなかった); 〜も needs the number standing beside it and is the everyday spoken way to exaggerate, so it appears in complaints and receipts alike.
Both deny the minimum, and only one of them needs a counter — 少しも…ない works on anything measurable or not (少しも変わらない), while 一〜も…ない needs a countable unit to put the 一 on, so it is the one that says "not a single X".
Opposite
- しか〜ないplain-antonym
The same count, opposite verdicts — 三つも says the speaker finds three a lot, 三つしかない says it is too few; しか always needs a negative predicate, while も takes one only in the 一〜も…ない shape.
Lookalikes
Same も, and the word in front of it changes the job — after a noun it adds one more item to something already established (雨も降った), after a number it stops adding and judges the SIZE of the amount, so no second item need appear in the sentence at all.
Same numeral, and the particle carries the whole claim — 三人で来た says they arrived as a party of three, 三人も来た says three came and that was more than the speaker bargained for.