Georgie Yes, 'once' and 'one time' indicate a singular occurrence. I only cooked at home once last week, Jiaying.
Jiaying Wow, you only cooked at home one time last week. 你上周只在家做了一次饭。而我在家里做了两次饭:I cooked at home twice. 我也可以说:I cooked at home two times.
Georgie 'Once' and 'one time', and 'twice' and 'two times' are generally interchangeable as adverbs, although 'once' and 'twice' are much more common because they're quicker and simpler to use, especially in spoken language.
接下来,说一说想表示事情在一段时间内发生的频率是 “多长时间一次/两次” 时,应该用哪个词。这里可以用副词 “once/twice + a + 单数形式的时间段” —— “twice a day(每天两次)”;或者 “once/twice + every + 复数形式的时间段” —— “once every two years(每两年一次)”。这里,“once” 和 “twice” 也可以用 “one time” 或者 “two times” 来替换,意思不变。听两个例句。
Examples Dentists advise that we brush our teeth twice a day. (牙医建议我们每天刷两次牙。)
I get my hair cut once every eight weeks. (我每八周剪一次头发。)
Jiaying 下面,我们来讲一讲在其它语境中可能遇到的情况。
Georgie When you're talking about 'time' as a noun, maybe you're referring to a couple of times you did something, or you're talking about an athlete's times.
Examples I'll call you once I leave work. (我离开单位后就给你打电话。)
Once you finish your homework, you can go out and play. (你一完成家庭作业,就可以出去玩了。)
Georgie So, the simple answer to your question is that, as adverbs, 'once' means the same as 'one time', and 'twice' means the same as 'two times'. They're synonyms that mean either one or two occurrences. We've also explained some subtle differences.
Georgie Remember, if you have a question about the English language you'd like to ask us, please send us an email. Our email address is: questions.chinaelt@bbc.co.uk