Seven percent would be possible for orders for, say, 500 or more.
订购500台或500台以上都不得有可能给予7%的折扣。
Precautions of this sort are necessary, for it is impossible to foretell the exact nature of the difficulties which will confront the pot-holer.
作出这样的准备是必要的,因为无法预见到洞穴探险者究竟会遇到什么性质的困难。