在实验室中，下列实验室药品的保存方法正确的是：①白磷保存在冷水中 ②Na、K保存在水里 ③HF溶液保存在塑料瓶中 ④AgNO3固体保存在棕色试剂瓶内 ⑤浓硝酸保存在棕色广口瓶内（ ）
A．①③④
B．③④
C．①②③④
D．①②③④⑤
答案：A
题目分析：①正确。②Na、K会与水反应。③正确，因为氢氟酸会腐蚀玻璃。④硝酸银溶液见光会分解，所以保存在棕色试剂瓶内。⑤浓硝酸有挥发性，所以要保存在细口瓶中。
点评：考查的是某些化学物质的特殊性质，所以保存方法也比较特殊。属于基础知识的考查，难度不大。
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| A true friend is always helpful. I didn't believe it. __1__ one thing happened (发生) to me when I was in Grade 7. Li Jie was one of my classmates. He and I were also neighbors. He always listened to his mother __2__. I didn't like listening to my mother. I didn't think it was necessary for__3__ to teach me anything. Li Jie knew all about that but he said __4__ to me. One weekend, Li Jie __5__ me to watch a movie. I liked __6__ very much so I went to the cinema (电影院)__7__ him happily. The movie was__8__ the love between a mother and a son. After__9__ it, I began to know how great the love of the mother was. I felt __10__ that I didn't listen to my mother __11__ . I decided to think more about my mother __12__ about myself. After I told that to him, Li Jie smiled and said, "It's really __13__ for you to watch such a movie. That was a good choice (选择) for both you and me." Suddenly, I knew __14__ he invited me to watch the movie. Just at that time, I knew a true friend is always__15__ . | |||
| ( )1. A. when ( )2. A. but ( )3. A. she ( )4. A. something ( )5. A. invited ( )6. A. them ( )7. A. and ( )8. A. of ( )9. A. reading ( )10. A. sorry ( )11. A. again ( )12. A. and ( )13. A. bad ( )14. A. what ( )15. A. helpful | B. after B. and B. me B. nothing B. take B. him B. with B. in B. read B. happy B. after B. than B. interesting B. when B. important | C. if C. so C. her C. anything C. helped C. movies C. of C. for C. watching C. sad C. before C. or C. exciting C. why C. popular | D. until D. or D. us D. everything D. answered D. my mother D. to D. about D. watch D. interested D. while D. with D. necessary D. who D. kind |