When you want to ask a friend that usually goes to sleep quite late what time they went to bed, then you may ask in the following ways:
-Until what time were you up?
-What time did you go to bed last night?
-When did you go to sleep?
夜遅く寝ることの多い友人に何時に寝たのか尋ねたいなら、次の質問が使えます。
-Until what time were you up?
（何時まで起きていたの）
-What time did you go to bed last night?
（昨日は何時に寝たの）
-When did you go to sleep?
（何時に寝たの）
Stay up - to be awake, to not be in bed
'I'd like to stay up an extra hour Mum, as it's not a school night'
In spoken English, most people would probably say 'till' instead of the full word 'until'
''What time were you awake until last night? You're usually a night owl''
A night owl refers to someone who is often up late. The opposite, someone who is often up early, can be described as an 'early bird'.
●"Stay up"
（夜遅くまで寝ないでいる）
●"I'd like to stay up an extra hour, Mum, as it's not a school night."
（ママ、学校がないから、あと1時間起きていたい。）
●"What time were you awake until last night? You're usually a night owl."
（昨夜は何時まで起きていたの？いつもは夜型なのに。）
●"Night owl" ➔夜型タイプ
●"Early bird"➔朝方タイプ
If you want to know when someone went to bed you don't always have to ask the question directly to get the answer you could also ask 'How long did you stay up last night?' you would then know the answer
You could also ask 'What time did you fall asleep last night?' or 'What time did you go to bed last night?'
相手が何時に寝たのか知りたい時は、必ずしも直接的にそれについて尋ねる必要はありません。例えば、'How long did you stay up last night?'（昨日の夜は何時まで起きていたの）と尋ねても分かります。
また、
'What time did you fall asleep last night?'（昨日は何時に寝たの）
'What time did you go to bed last night?'（昨日は何時に寝たの）
と尋ねることもできます。
The two sentences you see provided above are great ways to ask your listener at what time they went to sleep. In the first sentence you will see the term hit the hay and in the second sentence you will see the term get some shut eye. Both of these terms means to sleep. These terms are appropriate for informal settings, like talking with close friends or family members.
上記二つの例文は、人に何時に寝たのか尋ねる素晴らしい言い方です。
一つ目の例には"hit the hay"、二つ目の例には"get some shut eye"という表現がそれぞれ使われています。これらはどちらも「寝る」という意味です。これらの表現は家族や親しい友人と話すときなどインフォーマルな場面に適しています。
We often use the phrase 'be up late' or 'stay up late' when talking about staying awake until late at night.
If you want to emphasize that it is a common behavior then you can say 'Were you up late again?' or 'Did you stay up late as usual?'.
Alternatively, we can talk about going to bed, getting to bed, going to sleep or getting to sleep. If I ask 'What time did you get to sleep?' it is a bit different from 'What time did you go to bed?' because some people may lie in bed for a long time before they fall asleep. For example, 'I went to bed at 10pm but I didn't get to sleep until 1am'.
夜遅くまで起きていることについて言うときは、'be up late' または 'stay up late' というフレーズがよく使われます。
「よくあること」ということを強調したければ、
'Were you up late again?'（また、遅くまで起きていたの）
'Did you stay up late as usual?'（いつも通り夜更かししたの）
と言えます。
また、寝ることを表す言い方には、
'going to bed'
'getting to bed'
'going to sleep'
'getting to sleep'
があります。
'What time did you get to sleep?'（何時に眠りにつきましたか）は、'What time did you go to bed?'（何時に床につきましたか）とは少し違います、床についてから眠りにつくまでに長くかかることもありますから。例えば：
'I went to bed at 10pm but I didn't get to sleep until 1am'.
（10時に床についたけど、1時まで眠れませんでした）
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