搜题请搜索小程序“爱下问搜题”
问题 选择题

苏丹一号 (C16Hl2N2O)是一种染料。根据2004年4月的MSDS数据，该物质存在致癌证据，故不能用作食品添加剂。下列有关苏丹一号的说法正确的是

A．该物质属于氧化物            B．该物质中H、N元素质量比为6∶1

C．该物质中存在氮分子          D．该物质由C、H、O、N四种元素组成

答案

答案：D

A、该物质由C、H、O、N四种元素组成，并不是氧化物，故排除A；

B、该物质中H、N元素质量比为1×12：16×1═3：4；故排除B；

C、该物质由C16Hl2N2O分子构成，其中不含有氮分子，故排除C；

D、该物质由C、H、O、N四种元素组成，故D正确．

故选D

判断题

电子邮件可以进行一对多的邮件传递，即同一邮件可以一次发给许多人。（）
查看答案
单项选择题

Comparisons were drawn between the development of television in the 20th century and the diffusion of printing in the 15th and 16th centuries. Yet much had happened between. As was discussed before, it was not until the 19th century that the newspaper became the dominant pre- electronic (61) , following in the wake of the pamphlet and the book and in the (62) of the periodical. It was during the same time that the communications revolution (63) UP, beginning with transport, the railway, and leading on through the telegraph, the telephone, radio, and motion pictures into the 20th-century world of the motor car and the air plane. Not everyone sees that process in (64) . It is important to do so.

It is generally recognized, (65) , that the introduction of the computer in the early 20th century, (66) by the invention of the integrated circuit during the 1960s, radically changed the process, although its impact on the media was not immediately (67) . As time went by, computers became smaller and more powerful, and they became "personal" too, as well as (68) , with display becoming sharper and storage (69) increasing. They were thought of, like people, (70) generations, with the distance between generations much (71) .

It was within the computer age that the term "information society" began to be widely used to describe the (72) within which we now live. The communications revolution has (73) both work and leisure and how we think and feel both about place and time, but there have been (74) view about its economic, political, social and cultural implications. "Benefits" have been weighed (75) "harmful" outcomes. And generalizations have proved difficult.

（63）是（）

A.gathered

B.speeded

C.worked

D.picked
查看答案