问题
选择题
为防止食品变质,常在食品包装盒中用来吸收水分和氧气的物质是( )
A.生石灰
B.铁粉
C.碳酸氢钠
D.固体烧碱
答案
答案:B
题目分析:A、生石灰只能吸收水分,错误,B、利用铁粉生锈,是跟空气中的氧气和水反应,达到吸收水分和氧气,正确,C、碳酸氢钠既不吸收水分也不吸收氧气,错误, D、固体烧碱只能吸收水分,且具有强烈的腐蚀性,错误,故选B
为防止食品变质,常在食品包装盒中用来吸收水分和氧气的物质是( )
A.生石灰
B.铁粉
C.碳酸氢钠
D.固体烧碱
答案:B
题目分析:A、生石灰只能吸收水分,错误,B、利用铁粉生锈,是跟空气中的氧气和水反应,达到吸收水分和氧气,正确,C、碳酸氢钠既不吸收水分也不吸收氧气,错误, D、固体烧碱只能吸收水分,且具有强烈的腐蚀性,错误,故选B
改正句中的一处错误。 | |
1. Where's Wuhan and Changsha? 2. Where're the flowers? It's on the table. 3. There is a picture book on dresser. 4. There's a window(窗户)on the wall. 5. We can see some birds on the tree. 6. I need my hat. Please take it here. 7. It's on the floor, between the bookcase or the desk. 8. We aren't know his name. 9. Some things are in the bed. 10. Here is the CDs. | _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ |