Usage note
“正在”表示动作现在正在进行中，常放在动词前面。
“zhèngzài” biǎoshì dòngzuò xiànzài zhèngzài jìnxíng zhōng, cháng fàng zài dòngcí qiánmiàn.
“正在” means an action is happening right now, and it is usually placed before the verb.
Context note
“正在”用来表示一个动作现在正在进行中，常常用在日常生活的描述里。
"Zhèngzài" yòng lái biǎoshì yīgè dòngzuò xiànzài zhèngzài jìnxíng zhōng, chángcháng yòng zài rìcháng shēnghuó de miáoshù lǐ.
This word is used to show that an action is happening right now, and it often appears when talking about daily activities.
5 examples
妈妈正在做饭。
mā ma zhèng zài zuò fàn。
Mom is cooking.
我们正在学习中文。
wǒ men zhèng zài xué xí zhōng wén。
We are learning Chinese.
他正在看书。
tā zhèng zài kàn shū。
He is reading a book.
小猫正在玩玩具。
xiǎo māo zhèng zài wán wán jù。
The kitten is playing with toys.
爸爸正在开车。
bà ba zhèng zài kāi chē。
Dad is driving the car.
5 mini stories
妈妈正在做饭，小明正在写作业。
mā ma zhèng zài zuò fàn， xiǎo míng zhèng zài xiě zuò yè。
Mom is cooking, and Xiaoming is doing his homework.
我们正在学习中文，但是妹妹正在看电视。
wǒ men zhèng zài xué xí zhōng wén， dàn shì mèi mei zhèng zài kàn diàn shì。
We are learning Chinese, but our sister is watching TV.
他正在看书，突然电话响了。
tā zhèng zài kàn shū， tū rán diàn huà xiǎng le。
He was reading a book when the phone rang suddenly.
小猫正在玩玩具，但是妈妈叫它吃饭。
xiǎo māo zhèng zài wán wán jù， dàn shì mā ma jiào tā chī fàn。
The kitten is playing with toys, but Mom calls it to eat.
爸爸正在开车去上班，路上遇到了堵车。
bà ba zhèng zài kāi chē qù shàng bān， lù shang yù dào le dǔ chē。
Dad was driving to work when he encountered a traffic jam on the way.
Mini dialogue
做功课
A
你在做什么？
Nǐ zài zuò shénme?
What are you doing?
B
我正在写汉字。
Wǒ zhèngzài xiě Hànzì.
I am currently writing Chinese characters.
打电话
A
妈妈正在做饭吗？
Māma zhèngzài zuò fàn ma?
Is mom currently cooking?
B
对，她正在厨房忙。
Duì, tā zhèngzài chúfáng máng.
Yes, she is currently busy in the kitchen.
Related words and contrasts
similar
在
zài
at; in the process of
在 can also show an action is happening. 正在 is more formal for 'in the middle of doing'.
related
现在
xiànzài
now
正在 focuses on an ongoing action, 现在 means 'now' in general.