老师 + Verb / Number + 个 + 老师
老师 means "teacher," a respectful title for someone who instructs or educates. It combines 老 (old/venerable) with 师 (master). It is also used as a polite form of address, even outside academic settings.
王老师教我们数学。
Wáng lǎoshī jiāo wǒmen shùxué.
Teacher Wang teaches us math.
老师,这道题我不太明白。
Lǎoshī, zhè dào tí wǒ bú tài míngbai.
Teacher, I don't quite understand this problem.
她长大以后想当一名老师。
Tā zhǎng dà yǐhòu xiǎng dāng yī míng lǎoshī.
She wants to become a teacher when she grows up.