peripheral
adj
1 ~ (to sth) of secondary or minor importance (to sth) 次要的; 不重要的
topics peripheral to the main theme 围绕中心议题的小题目.
2 of or on a periphery 外围的; 边缘的
peripheral zones 边缘地带.
Pierre and I borrowed the money and bought the necklace. During the next ten years we both worked day and night to pay back the money we had borrowed. That's why I now look so old. Well, after all these years we've at last paid back all the money.