能影响水的电离平衡,并使溶液中的c(H+)>c(OH-)的操作是( ) A.向水

题型:选择题

问题:

能影响水的电离平衡,并使溶液中的c(H+)>c(OH-)的操作是(  )

A.向水中投入一小块金属钠

B.将水加热煮沸

C.向水中通入二氧化碳气体

D.向水中加食盐晶体

考点:水电离的影响因素水的电离平衡
题型:选择题

﹣3﹣(﹣5)=(    )

题型:选择题

关于光的反射定律,以下说法正确的是    [ ]

A.反射光线和入射光线不可能在同一直线上  

B.入射角不一定等于反射角   

C.在漫反射中.每条光线不一定遵守光的反射定律   

D.在反射现象中,光路是可逆的

题型:选择题

CPU中,除了内部总线和必要的寄存器外,主要的两大部件分别是运算器和

A.控制器

B.存储器

C.Cache

D.编辑器

题型:选择题

关于骨软骨瘤的临床表现,下列哪些不符合

A.多见于年轻人

B.多发生于干骺端

C.生长年龄结束后肿瘤不停止生长

D.1%的患者可以恶化

E.单发性骨软骨瘤比多发性恶变机会少

题型:选择题

Questions 11 to 15 are based on the following passage: ( 10 分 )In the United States, it is important to be on time, or punctual, for an appointment, a class, a meeting, etc. However, this may not be true in all countries. An American professor discovered this difference while teaching a class in a Brazilian university. The two-hour class was scheduled to begin at 10 a.m. and end at 12. On the first day, when the professor arrived on time, no one was in the classroom. Many students came after 10 a.m. Several arrived after 10:30 a.m. Two students came after 11 a.m. Although all the students greeted the professor as they arrived, few apologized for their lateness. Were these students being rude He decided to study the students’ behavior.The professor talked to American and Brazilian students about lateness in both an informal and a formal situation: at a lunch with a friend and in university calls, respectively. He gave them anexample and asked them how they would react. If they had a lunch appointment with a friend, the average American student showed clearly lateness as 19 minutes:after the agreed time. On the otherhand, the average Brazilian student would be 33 minutes late.In an American university, students are expected to arrive at the appointed hour. In contrast, inBrazil, neither the teacher nor the students always arrive at the appointed hour. Classes not onlybegin at the scheduled time in the United States, but also end at the scheduled time. In the Brazilianclass, only a few students left the class at 12:00; many remained past 12:30 to discuss the class andask more questions. Arriving late may not be very important in Brazil, neither is staying late.

What does this passage tell us

A.People learn the importance of time from the country in which they live.

B.The importance of being on .time differs among cultures.

C.Students being late for class should explain the reason to their teacher.

D.It is important to come to class on time in the united States.It is important to come to class on time in the united States.

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