①蔬菜保鲜效果较好的条件是0℃以上低温及低氧

②用自来水洗净鸡肉，置于包装袋中并抽真空，不冷冻也可保持数年不变质

③种子入库前须进行干燥处理，目的是降低含水量，以减少营养物质的消耗和避免种子发芽霉变

④因为天然织物含有大量的纤维素和蛋白质，一旦受潮，衣物上就会有霉菌等微生物寄生．

许多物理概念的得出过程和定义方法是很相似的，其中和速度不同的是（　　）

—Don't you think it's ________ waste of time?

阅读短文完成下列问题

Beckham in a Football Movie

    Do you like football? You must know David Beckham. But did you know that he was in a movie? He was David Beckham in the movie Goal.

    Beckham said, "I want to teach kids how to play football when I finally hang up my boots." "I believe that Goal can send a positive message to kids around the world.”

    Beckham, 37, said, "I think that Goal can make football more popular in America and Asia. I am very happy because I can help do it.”