得
de
得 is a window that opens behind the verb
The picture You say the verb, and a window swings open behind it. Through that window you see how it turned out. Before the verb it is 地, after the verb it is 得. 慢慢地走 is how the walking looks; 走得很慢 is how the walking turned out.
Where the picture shows up in 得
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the window shows how fast
他跑得很快。
tā pǎo de hěn kuài
He runs really fast.
A window opens behind the runner, and inside it a stopwatch hand is whipping around.
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the window shows if it landed
你说得对。
nǐ shuō de duì
You are right about that.
The moment he stops talking, the window behind shows an arrow dead in the centre of the target.
-
the window shows how well
我昨天晚上睡得不好。
wǒ zuótiān wǎnshang shuì de bù hǎo
I slept badly last night.
Behind the sleeping, the window shows a blanket churned up from a whole night of turning over.
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the window shows if it is possible
这个箱子我搬得动。
zhège xiāngzi wǒ bān de dòng
I can move this box myself.
Behind the lifting, the window shows the underside of the box actually clearing the floor.
Verb plus 得 plus result means you can reach that result. The negative is 搬不动.
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the window shows the timing
你今天来得太早了。
nǐ jīntiān lái de tài zǎo le
You have come far too early today.
Behind the arriving, the window shows an empty meeting room with nothing but rows of chairs.
Before the verb it is 地; after the verb it is 得. 慢慢地走 is how the walking looks, 走得很慢 is how the walking turned out.
All of it in one picture
Behind the running, a stopwatch spinning; behind the speaking, an arrow in the centre of the target. Behind the sleeping, a churned-up blanket; behind the lifting, a box off the floor; behind the arriving, a room with nobody in it. What the window shows is never the action itself but the mark the action left. That is why whatever follows 得 answers how it came out, not what was done.