把食品分为罐头食品、冷冻食品、腌渍食品等的标准是()。
A.食品的加工程度
B.食品的加工方法
C.食品的保藏方法
D.原料种类
参考答案:C
This is the school _____ they visited last year and is the one _____ my father once worked.
A.that; where
B.where; that
C.where; where
D.that; that
下列哪一种毒气是无色无味的?()
A.氯气
B.一氧化碳
C.二氧化硫