Usage note
倍用来表示数量的增加，比如一倍、两倍等。
bèi lái bǎo shì nù liàng de zēng jiā, rú guǒ yī bèi、liǎng bèi děng。
倍 is used to indicate an increase in quantity, such as one times, two times, etc.
Context note
倍常用于描述时间的增加，比如一天比一天多，或者一小时等于两小时。
bèi cháng yòng lái miáo shù shí jiān de zēng jiā, rú guǒ yī tiān bǐ yī tiān duō, huò zhě yī xiǎoshí děng yú liǎng xiǎoshí。
倍 is commonly used to describe an increase in time, such as one day being more than another, or one hour equaling two hours.
5 examples
一天比一天多一倍。
yì tiān bǐ yì tiān duō yí bèi。
One day is more than the previous day by one times.
两小时等于四倍的时间。
liǎng xiǎo shí děng yú sì bèi de shí jiān。
Two hours equal four times the time.
每天学习时间增加一倍。
měi tiān xué xí shí jiān zēng jiā yí bèi。
Daily study time increases by one times.
这个项目比上个项目的规模大两倍。
zhè ge xiàng mù bǐ shàng gè xiàng mù dì guī mó dà liǎng bèi。
This project is twice the scale of the last project.
每天多做一倍的练习。
měi tiān duō zuò yí bèi de liàn xí。
Do one times more practice every day.
5 mini stories
小明每天学习时间增加了一倍，现在他每天学两个小时。
xiǎo míng měi tiān xué xí shí jiān zēng jiā le yí bèi， xiàn zài tā měi tiān xué liǎng gè xiǎo shí。
Xiaoming increased his study time by one times, now he studies for two hours a day.
妈妈说这个月的工资是上个月的两倍。
mā ma shuō zhè ge yuè de gōng zī shì shàng gè yuè de liǎng bèi。
Mom said this month's salary is twice that of last month.
每天多做一倍的练习，学习效果更好。
měi tiān duō zuò yí bèi de liàn xí， xué xí xiào guǒ gèng hǎo。
Do one times more practice every day, and the learning effect will be better.
这个周末的时间是平时的三倍。
zhè ge zhōu mò de shí jiān shì píng shí de sān bèi。
This weekend is three times as long as usual weekdays.
每天多睡一倍，感觉精力更充沛了。
měi tiān duō shuì yí bèi， gǎn jué jīng lì gèng chōng pèi le。
Sleep one times more every day, and feel more energetic.
Mini dialogue
比较苹果
A
这个苹果比那个大一倍。
Zhège píngguǒ bǐ nàge dà yī bèi.
This apple is twice as big as that one.
B
真的吗？看起来大很多。
Zhēn de ma? Kàn qǐlái dà hěnduō.
Really? It looks much bigger.
跑步进步
A
我跑步的速度快了两倍。
Wǒ pǎobù de sùdù kuài le liǎng bèi.
My running speed is twice as fast.
B
你真厉害！
Nǐ zhēn lìhài!
You're amazing!
Related words and contrasts
related
加倍
jiā bèi
to double
加 means add, so 加倍 means to double or increase greatly.
related
倍数
bèi shù
multiple (math)
倍数 is the noun for a mathematical multiple.