“Although”: suírán . . . , kěshi . . . 虽然 . . - Cchatty

“Although”: suírán . . . , kěshi . . . 虽然 . . . , 可是 . . . means “although . . . , but . . .”

In any sentence that begins with suírán 虽然, the second clause must start with kěshì 可是 or dànshì 但是:

Although I’m tired, (but) I don’t want to go to bed.
Suírán wǒ lèile, kěshi (dànshi) wǒ búyào shàngchuáng.
虽然我累了，可是 (但是) 我不要上床。

NOTE: Adjective + shì 是 + adjective, kěshi/dànshi 可是/但是 . . . (less formal than suírán . . . kěshi . . . 虽然 . . . , 可是 . . . and generally limited to adjectives)

Although that restaurant is expensive, (but) the food is delicious.
Nèige cānguǎn guì shì guì, kěshi (dànshi) cài hěn hǎochī.
那个餐馆贵是贵，可是 (但是) 菜很好吃。