What's "all along" mean and when's it used?

Native speaker’s answer
Rebecca
"All along" means "the whole time" or from the beginning of something. It's used when you want to mention the whole duration of something while something else happens. It's also often used when something happens without knowing or being aware of it until a point in time, like a contrast of two things. Ex: You were lying to me all along?! Ex: Maybe something was wrong all along. Ex: You were honest all along, but I didn't believe you. = You were honest this whole time, but I didn't believe you.