Unit 3 Inventors and inventions
高考试卷分块专练
Ⅰ.完形填空
Resealable (可密封的) plastic bags — sometimes called by a brand name, such as Ziploc® — are those little clear plastic bags you use to keep your sandwiches and chips fresh. They usually have some sort of sealing mechanism, like a plastic zipper, which allows you to seal the bag to keep __1__ out.
Keeping air away from __2__ allows them to stay fresh longer. Bacteria and other organisms in the air will __3__ food items over time if allowed to come into __4__ with them. Sealed plastic bags keep these organisms __5__ getting to your food.
