防止食品腐败可以采用不同的方法，对香菇这种食品的保存方法常采用（ ）
世界面积最大的国家是（ ）
听短文, 根据短文内容完成下列表格。
Things some people do on the __（1）____
they spend only ____（2）____.
They ___（3）____ to give their seats to the old people without listening to the ticket sellers.
Be ___（4）____ and help the persons in need of help.
Things we should do
Give your seats to the people with ____（5）____ and let old people get on or get off before you.
