Subject + 问 + (Person) + Question
The verb 问 (wèn) means "to ask" and is used when posing a question to someone. It can take both a person and a question as objects, as in 问他一个问题 (ask him a question).
我想问你一个问题。
Wǒ xiǎng wèn nǐ yī ge wèntí.
I want to ask you a question.
她问我明天有没有空。
Tā wèn wǒ míngtiān yǒu méiyǒu kòng.
She asked me if I'm free tomorrow.
有什么不懂的就问老师。
Yǒu shénme bù dǒng de jiù wèn lǎoshī.
If there's anything you don't understand, just ask the teacher.