Be sure to buy in a lot of tinned food in case we're snowed up.一定要多买些罐头食品以防我们被雪困住。It's usually cheaper to buy in bulk.批量购买通常比较便宜。It may be advantageous to buy in bulk.批量购买也许会有利。People had to buy in candles during the electricity strike.电厂工人罢工期间，人们不得不大量购买蜡烛。