Riding my bike up that steep hill was exhausting, but reaching the top and seeing the ocean was worth it.

was 是 be 动词的过去式，表示"是"或"存在"的状态。 worth 是形容词，意思是"值得的"，表示某事物有价值或重要性。 it 是代词，在这里指代前面提到的"骑车上山并看到大海"的整个经历。 was worth it 这个短语表示"是值得的"，强调虽然过程辛苦但结果令人满意。