Clause₁ + 但是 + Clause₂
但是 means "but" or "however" and introduces a contrasting clause. It is slightly more formal than 可是 and is common in both written and spoken Chinese. For example, 他很聪明,但是不努力 means "He is smart, but not hardworking."
我听懂了,但是不会说。
wǒ tīng dǒng le, dànshì bú huì shuō.
I understood what was said, but I can't speak it.
这道菜好吃,但是有点辣。
zhè dào cài hǎochī, dànshì yǒudiǎn là.
This dish is delicious, but it's a bit spicy.
外面很热,但是房间里很凉快。
wàimiàn hěn rè, dànshì fángjiān lǐ hěn liángkuai.
It's very hot outside, but it's cool inside the room.