on approval

详细解释:商品供试用的, 包退包换的
【经】 (商品)供试用, 包退包换

英语解释：

副词 on approval:

for examination (with an option to buy)

例句：

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.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。