1. 快餐;便餐
    A snack is a simple meal that is quick to cook and to eat.

    e.g. Lunch was a snack in the fields.
           午饭是在野外吃的便餐。

2. 小吃;零嘴
    A snack is something such as a chocolate bar that you eat between meals.

    e.g. Do you eat sweets, cakes or sugary snacks?
           你吃糖果、蛋糕或甜点吗？

3. 吃小吃;吃点心
    If you snack, you eat snacks between meals.

    e.g. Instead of snacking on crisps and chocolate, nibble on celery or carrot...
           不要把薯片和巧克力当零食来吃，要吃些芹菜和胡萝卜。
    e.g. She would improve her diet if she ate less fried food and snacked less.
           如果她少吃油炸食品和零食的话，她的饮食结构就会有所改观。