grammar → (雖然)…可是…
TSUMUGU · TBCL 2 (est.) · 語法
(雖然)…可是… grammar point · tier 2 · concession with 可是 (although) … but …
Concession: grant one thing, then pivot to what actually holds; the granting clause can drop, the pivot cannot.

Hook inherited from 雖然…但是….

Concession
框 · Frame
(雖然 [granted],)可是 [what holds]
觸 · Trigger
You concede a point, then steer to the part that decides it.
序 · The move
1State the thing you are willing to grant.Is this the point you can give away?
2Mark the turn with 可是.Does the real weight sit after 可是, not before?
3Drop 雖然 if the grant is already plain.Can 可是 stand alone and still carry the turn? It can; 雖然 cannot.
例 · Examples
1雖然although (droppable opener)他不是很有錢,可是but (the pivot that lands the weight)他很快樂。
Although he isn't very rich, he's very happy.
界 · Boundary
雖然…但是…
Same concession; 可是 is the lighter, conversational pivot, 但是 the heavier, more written one. Both turn the line.
可以 (may, can)
可是 is a two-syllable turn-word at a clause seam; 可以 is permission/ability before a verb. The 是 vs 以 second char splits them.
✗ 雖然他有錢。 → ✓ 雖然他有錢,可是… (the 雖然 grant needs the 可是 turn to land)
✗ 他有錢可是很小氣。 → ✓ 他有錢,可是很小氣。 (可是 opens the second clause; a comma sits before it)
✗ 雖然他沒有錢,可是他很快樂。當作重點是「沒錢」 → ✓ 雖然他很快樂,可是他沒有錢。 (the point that holds goes after 可是; don't put the throwaway grant there)
English lets "although" stand alone with no second connector ("Although he's poor, he's happy"). Chinese keeps the pivot 可是 even when 雖然 is present; 雖然 is the droppable one, not 可是.