〜が、〜
But (joins two clauses in one sentence); also used to open a remarkmachine translation
FormationClause 1 + が、+ Clause 2
Put が at the end of the first clause to join it to a second clause with a contrasting idea, like "but" in Vietnamese. In polite speech, the clause before が usually takes the polite form: 難しいですが、….
が is also used to open a remark before asking a question or making a request: すみませんが、…. Here が doesn't mean "but" — it just softens the sentence and makes it more polite.
Distinguish it from でも: が joins two clauses within the same sentence, while でも stands at the start of a new sentence.
Examples
日本語は難しいですが、面白いです。
Japanese is difficult but interesting.
すみませんが、駅はどこですか。
Excuse me, where is the station?
昨日デパートへ行きましたが、何も買いませんでした。
I went to the department store yesterday, but I didn't buy anything.