在
zài
在 is one pin stuck in the map
The picture A hand pushing a pin into a map. People, actions and even times all sit on that pin.
Where the picture shows up in 在
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a person on the pin
我在公司，你呢？
wǒ zài gōngsī, nǐ ne
I am at the office, where are you?
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a thing on the pin
钥匙在桌子上。
yàoshi zài zhuōzi shang
The keys are on the desk.
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where the action happens
请在这里签名。
qǐng zài zhèlǐ qiānmíng
Please sign here.
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the pin called now
他在打电话，等一下。
tā zài dǎ diànhuà, děng yíxià
He is on the phone, one moment.
在 plus a verb is not separate grammar. It just pins the action to the spot called now.
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the pin on the clock
会议在下午两点开始。
huìyì zài xiàwǔ liǎng diǎn kāishǐ
The meeting starts at two in the afternoon.