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问题 选择题

下列说法正确的是（　　）

A．纯净物一定由分子构成

B．同种分子构成的物质一定是纯净物

C．混合物肯定由两种以上元素组成

D．盐中一定含有金属元素

答案

A、有的纯净物由分子构成，例如氧气；有的纯净物由原子构成，例如铁；有的纯净物由离子构成，例如氯化钠，故A说法错误；

B、同种分子构成的物质一定是一种物质，属于纯净物，故B说法正确；

C、混合物由两种以上的物质组成，故C说法错误；

D、盐中不一定含有金属元素，例如硝酸铵，故D说法错误．

故B．

单项选择题

信息隐蔽的概念与下述哪一种概念直接相关( )

A．软件结构定义

B．模块独立性

C．模块类型划分

D．模拟耦合度
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单项选择题

College sports in the United States are a huge deal. Almost all major American universities have football, baseball, basketball and hockey programs, and (1) millions of dollars each year to sports. Most of them earn millions (2) as well, in television revenues, sponsorships. They also benefit (3) from the added publicity they get via their teams. Big-name universities (4) each other in the most popular sports. Football games at Michigan regularly (5) crowds of over 90, 000. Basketball’s national collegiate championship game is a TV (6) on a par with any other sporting event in the United States, (7) perhaps the Super Bowl itself. At any given time during fall or winter one can (8) one’s TV set and see the top athletic programs--from schools like Michigan, UCLA, Duke and Stanford-- (9) in front of packed houses and national TV audiences.

The athletes themselves are (10) and provided with sch61arships. College coaches identify (11) teenagers and then go into high schools to (12) the country’s best players to attend their universities. There are strict rules about (13) coaches can recruit--no recruiting calls after 9 p. m. , only one official visit to a campus--but they are often bent and sometimes (14) . Top college football programs (15) scholarships to 20 or 30 players each year, and those student-athletes, when they arrive (16) campus, receive free housing, tuition, meals, books, etc.

In return, the players (17) the program in their sport. Football players at top colleges (18) two hours a day, four days a week from January to April. In summer, it’s back to strength and agility training four days a week until mid-August, when camp (19) and preparation for the opening of the September-to-December season begins (20) During the season, practices last two or three hours a day from Tuesday to Friday. Saturday is game day. Mondays are an officially mandated day of rest.

7（）

A. save

B. saving

C. saved

D.to save
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