A2
在 before the verb — happening now
How Chinese marks an action in progress with 在 and 正在, why 呢 turns up at the end of these sentences, and why 我在住在北京 is wrong however natural “I’m living in Beijing” sounds.
在 in front of a verb says the action is going on right now. It is the same character as the 在 that marks location — Chinese treats being in the middle of doing something as a kind of place to be.
我在吃飯。
Wǒ zài chīfàn.
I’m eating.
他在看電視。
Tā zài kàn diànshì.
He’s watching television.
正在 for this exact moment
正 sharpens it to right now, as we speak. It is what you reach for when the timing is the point — someone rang and you are in the middle of something.
他正在開會。
Tā zhèngzài kāihuì.
He’s in a meeting right now.
我正在做飯，等一下。
Wǒ zhèngzài zuò fàn, děng yíxià.
I’m cooking, hang on.
呢 at the end
呢 softens the sentence and marks it as ongoing. It appears constantly with this pattern, often instead of 在 rather than alongside it, and it makes a question sound conversational rather than clipped.
你在做什麼呢？
Nǐ zài zuò shénme ne?
What are you up to?
他睡覺呢。
Tā shuìjiào ne.
He’s asleep.
Not for states
This is the mistake English speakers make, and it is invisible from the English side because English uses its progressive for both. 在 marks an action under way. Living somewhere, knowing something, owning something and liking something are not actions.
我在住在北京。
我住在北京。
I’m living in Beijing is progressive in English and a plain statement in Chinese. The same goes for 我知道, 我有, 我喜歡 — none of them take 在.
The negative
沒在, or 沒有在. 不在 would be read as the location 在 — not at — which is a different sentence.
我沒在看電視。
Wǒ méi zài kàn diànshì.
I wasn’t watching television.
Against 著
在 says the action is running. 著 says a state left behind by an action is holding. 他在開門 is he’s opening the door; 門開著 is the door is open. One is a film, the other a photograph.