The structure 一会儿…一会儿… is used to indicate alternating actions or situations. For example: "now it's cold, before it was hot".
It can be used to relate words, phrases and sentences.
You can also use the structure without erization 一会…一会… .
Now it's cold, before it was hot
yí huìr lěng yí huìr rè
One moment she says yes, and the next she says no
tā yí huì shuō kěyǐ, yí huì shuō bù xíng
I don't usually work hard. Sometimes I study, sometimes I play
wǒ píngshí bú tài nǔlì, yí huì xuéxí yí huì wánr
The structure 一时…一时…
The structure 一时…一时… has a similar meaning. It emphasizes that two actions or situations come one after another or are periodically repeated.
In this structure, adjectives, verbs, or phrases can be placed after 一时.
When I was sick, one moment I felt cold and the next moment I felt hot
wǒ shēngbìng de shíhòu yǒu le yì shí lěng yì shí rè de gǎnjué
I really don't understand his tempermant. Sometimes he's happy, sometimes he's melancholy
tā de píqì wǒ zhēn bù dǒng, yì shí gāoxìng, yì shí yōuyù
It's normal that our projects sometimes succeed, and sometimes fail
wǒmen de xiàngmù yì shí chénggōng, yì shí shībài, hěn zhèngcháng de
一时 can be used independently. It is placed before the predicate.
He lost his train of thought for a moment, but then he recovered it
tā yīshí duàn le sīlù, jiēzhe yòu chóngxīn xiǎngqǐlái le
I don't have that much money now. Can I have a few days of grace?