问题 选择题

下列有关实验原理、操作及安全知识的叙述,正确的是

A.不慎将苯酚固体粉末沾在皮肤上,立即用大量热水(>65℃)冲洗

B.在用标准盐酸滴定未知浓度NaOH溶液时,滴定前,酸式滴定管尖嘴处有气泡,而在滴定后气泡消失,会使测定结果偏低

C.把玻璃管插入橡胶塞孔时,可用厚布护手,紧握用水湿润的玻管,缓慢旋进塞孔中

D.银氨溶液、Cu(OH)2悬浊液、硫酸溶液、氯水在实验室里均不宜长期放置

答案

答案:C

正确答案:C

A、不正确,形成溶液后,污染面积更大;B、不正确,酸式滴定管尖嘴处有气泡,而在滴定后气泡消失,气泡的体积,也当成的标准盐酸的体积,会使测定结果偏高; C、正确,玻璃管易碎,注意安全,防止玻璃管折断时划伤手;D、不正确,其中硫酸性质稳定,可以长时间保存。

完形填空

Though different educational systems have different purposes, one thing is certain: all students should take part in examinations.

___1___ the English educational system, students take ___2___ very important ___3___. The first is the eleven-plus, which is taken at the age of eleven ___4___ past. At one time the ability ___5___ on the eleven-plus would have determined ___6___ a child stayed in school. ___7___, however, all children continue in “comprehensive”(综合性的) schools, and the eleven-plus determines which courses of study the child will follow. At the age of fifteen or sixteen, the students are tested for the Ordinary Level of the General Certificate(证书) of Education. This examination covers a wide ___8___ of subjects; once students have passed this exam, they are ___9___ to specialize, so that two-thirds or ___10___ of their courses will be ___11___ physics, chemistry, classical language, or ___12___ they wish to study ___13___. The ___14___ examination, at eighteen, covers only the ___15___ of the special subjects. ___16___ the universities, students study only in their concentrated area, and ___17___ students ever venture(冒险) outside ___18___ subject again; ___19___, the English boy or girl is a specialist ___20___ the age of fifteen.

1. A. On  B. In       C. To      D. For

2. A. four       B. three   C. two     D. one

3. A. subjects  B. languages   C. courses       D. examinations

4. A. somewhat      B. or else C. or so   D. or rather

5. A. seen       B. heard  C. shown D. known

6. A. when      B. if C. that     D. how

7. A. But B. Then   C. So      D. Now

8. A. number  B. part    C. range  D. collection

9. A. allowed  B. passed C. forbidden   D. admit

10. A. much    B. many  C. more   D. most

11. A. in  B. of       C. with    D. on

12. A. whenever     B.however      C.whatever D. wherever

13. A. at all costs    B. at the same time      C. at the least   D. at great length

14. A. late      B. later    C. early   D. final

15. A. context B. content         C. book   D. lesson

16. A. Even so       B. Even if      C. Even then   D. Even at

17. A. few      B. no      C. some   D. any

18. A. that      B. their   C. its       D. which

19. A. in any case   B. in all C. in a sense   D. in the end

20. A. of B. from C. at       D. under

填空题