He abandoned his hobbies when his responsibilities came along.

came 是动词 come 的过去式，表示"来、到来"的动作。 along 在这里是副词，表示"一起、伴随"的意思，强调与责任同时出现的情况。 came along 这个短语表示"出现、到来"，常用来描述某种情况或机会的突然出现。