Learn Hardcore Chinese: shàng dàxué yǐqián, tā chángcháng gēn wǒ tǎolùn zìjǐ xiǎng xué shénme zhuānyè. - Before going to university, he often discussed with me what major he wanted to study.

Breakdown of shàng dàxué yǐqián, tā chángcháng gēn wǒ tǎolùn zìjǐ xiǎng xué shénme zhuānyè.

What does 上大学 mean literally? Is 上 a verb here?

Literally, 上大学 is “to go up to / attend university”.

上 (shàng) is a verb meaning “to go up, to attend, to go to (a class/school/work).”
大学 (dàxué) is “university / college.”

So 上大学 together means “to attend college / go to college,” not “on college.”
In Chinese, 上 is commonly used like this:

So in the sentence, 上大学 is a verb phrase (“attend college”), not a prepositional phrase.

Why is it 上大学以前 and not 以前上大学?

Both 上大学以前 and 以前上大学 are grammatical, but they feel different:

上大学以前: “Before attending college”
- Focus is on the specific event of attending college, then marking “before” after it.
- This order ([event] + 以前) is the most natural and common for “before doing X.”
以前上大学: literally “in the past, (he) attended college”
- Here 以前 means “before / in the past” in a more general, looser sense.
- It usually describes a general past habit or state, not “before doing X.”

In this sentence we’re talking about a period before the event of going to college, so:

上大学以前，……

is the natural choice to mean “Before he went to college, …”

Why is there no explicit subject in 上大学以前? Who is the subject of that clause?