んだけど / ですが

A sentence + んだけど / ですが can be used as a "preliminary remark by the speaker to inform the hearer of the speaker's desire, the current situation, etc." Following this statement, there is often a question related to that desire/situation, asking for advice, or making some other type of request. Although けど and が translate to English as "but", we wouldn't necessarily use "but" when translating these sentences because it provides a different type of open-ended meaning.

先生、この文法がよく分からないんですが・・・
Sensei, I don't understand this grammar very well, so... (could you please explain it to me?)

今夜の月がきれいんですが、一緒に見に行きませんか？
The moon is beautiful tonight, so do you want to go see it together?

友達の誕生日にプレゼントを送りたいんだけど、何がいいと思う。
I want to send my friend a present for his birthday, so what do you think would be good?

この映画、面白そうなんだけど、一緒に見に行かない？
This movie looks interesting, so why don't we go see it together?

I know that I used "so" in all of these translations, which may make it sound like these sentences need から instead. But から implies a stronger "because" or "since" meaning in the first half of the sentence, which isn't really the case with these situations.