问题 选择题

明胶,可以在制药与食品工业中使用.明胶里含有多种蛋白质,其中某蛋白质在人体内水解产物之一为苯丙氨酸(化学式为C9H11O2N).下列对相关物质的说法正确(  )

A.一个苯丙氨酸分子由23个原子构成

B.苯丙氨酸分子由碳、氢、氧、氮四种元素组成

C.苯丙氨酸中碳、氢、氧、氮四种元素质量比为 9:11:2:1

D.苯丙氨酸中氢元素的质量分数最大

答案

A、一个苯丙氨酸分子是由9个碳原子、11个氢原子、2个氧原子和1个氮原子构成的,则一个苯丙氨酸分子由23个原子构成的,故选项说法正确.

B、分子是由原子构成的,苯丙氨酸分子由碳、氢、氧、氮四种原子构成的,故选项说法错误.

C、苯丙氨酸中碳、氢、氧、氮四种元素质量比为(12×9):(1×11):(16×2):14≠9:11:2:1,故选项说法错误.

D、苯丙氨酸中碳原子的相对原子质量之和为12×9=108,氢原子的相对原子质量之和为1×8=8,氧原子的相对原子质量之和为16×2=32,氮原子的相对原子质量之和为14,碳元素的相对原子质量之和最大,则碳元素的质量分数最高,故选项说法错误.

故选A.

阅读理解

D

Lex Kim English School Information Session Description

Lex Kim English School offers language improvement courses in reading, writing, grammar, and speech to students from Grades 3 to 11. All classes are conducted in English and class sizes are no larger than 10 students.

We are looking for full-time teachers and assistant teachers who’re interested in very organized self-starters. Our application process includes a phone interview, an in-person interview, and a sample teaching period. Additionally, all applicants must standards for the available positions:

Native English speakers with at least 15 years’ experience in teaching

A Bachelor’s degree or higher (preferably in education, English, or related fields)

Benefits

Teacher pay ranges from $26,000 to $45,000 depending on experience plus overtime pay and various performance-based prizes throughout the year free dinners, and other benefits.

Required documents:

The cover letter ( please indicate the position you are applying for )

The resume(个人简历)with your Date     The recent photo of yourself or the copy of your passport

At least two references(推荐信)from your former employer

Contact

Please visit our website at www.lexkimjob.com for more information and visit http://lexkimjob.com/apply/main.php to submit(提交)your application.

53. According to the passage, Lex Kim English School _______.

A. only offers classes to the students in the morning

B. has students of all ages who are weak in English

C. is very strict about the application process

D. is badly in need of part-time English teachers

54. Who is the most likely to be hired by Lex Kim English School ?

A. A Frenchman with a Bachelor’s degree in education

B. An American with a Master’s degree in economics

C. A Korean with a Doctor’s degree who has worked in America for 18 years

D. An Englishman who has 16 years’ experience in teaching in a Canadian college

55. We can know from the passage that _______.

A. applicants must hand in their passports to the school

B. teachers of Lex Kim English School must use English to teach grammar

C. the more experienced applicants are, the higher pay they will get

D. applicants can go directly to the school to apply for the positions

单项选择题