I was in luck because my friend gave me a lift every day.

was 是 be 动词的过去式，表示"是"或"处于某种状态"。 in 是介词，表示"在...中"或"处于某种状态"。 luck 是名词，意思是"运气、幸运"。 was in luck 是一个固定短语，表示"很幸运"或"运气好"，指处于有利或幸运的情况中。