在 ... 之内在或进入里面；在内部 In or into the inner part; inside.
这工作一年之内不见得能完成。 The job is unlikely to be finished inside (of) a year.
商店送出供试用的货物在订购时必须付款，但顾客如在七天之内退货，就可将原款全部收回。 Goods sent on approval must be paid for at the time of ordering, but if goods are returned within7 days customers will get their money back in full.
