The 连…更不用说… structure is used to make sentences like:
"even I couldn’t do it, let alone you", "he can’t even run a kilometer, let alone run ten kilometers".
This structure can be used like this:
1) to say that two people — "A" and "B" — are not able to perform an action.
In this case, “A” is superior to “B” in that if “A” can’t do an action, then “B” definitely won’t be able to do that action.
The action is expressed with a verb or verb phrase in the negative form. The adverbs 都 or 也 are placed before a verb or verb phrase.
Even he can’t do it, let alone me
lián tā dōu bú huì, gèng búyòng shuō wǒ le
Even Xiao Ming didn’t pass the exam, let alone her
lián cōngmíng de xiǎolóng yě kǎobuliǎo, gèng búyòng shuō tā le
2) to compare the complexity levels of an action. In this case, we talk about the same person.
A simple action that a person cannot perform is placed after 连.
The more difficult action that he definitely can’t perform is placed after 更不用说.
A verb in the negative form is used as a predicate. The adverbs 都 and 也 are usually placed before a verb.
Both complements refer to the same predicate — that’s why the predicate is not mentioned the second time.
My sister didn’t even score 80 points, let alone 100 points
He can’t even write these few words, let alone a whole composition
tā lián zhè jǐ ge zì dōu bú huì xiě, gèng búyòng shuō xiě piān zuòwén le
更不用说 can be used separately. In this case, the simpler action is placed in the first part of a sentence. The more complex action, that “A” definitely can’t perform, is placed after 更不用说 in the second part of a sentence.
He can’t even boil eggs, let alone set a big table
tā dōu bú huì zhǔ jīdàn, gèng bú yòng shuō zuò yí dà zhuōzi de cài le
He never traveled far from his hometown, let alone travel abroad
tā cónglái méiyǒu chūguo yuǎnmén, gèng bú yòng shuō chūguó le