退火的主要目的是（）。 A.便于切削加工，消除内应力； B.增加硬度，细化晶粒； C

Now let’s look ourselves as a species in relation to ecosystem balance.Modern scientists believe that humankind, like other animals, evolved(进化) through millions of years of changes and adaptations to the environment and that our most direct evolutionary ancestor was probably an earlier species of the primate(monkey, ape) group. Despite this similarity with other creatures, however, the evolution of humankind differs from that of other species in one important and unique way.

In other species, evolution has led to specialization, both in the species abilities and in its place within the environmental structure. For example, the giraffe is much adapted to feeding on treetops, but it is also specialized and thus limited to feeding on trees and shrubs. Only with great difficulty can it bend down to graze on the ground. Similarly, the anteater is extremely well adapted to eating ants but is unable to catch or eat other animals. The same is true for countless other species.

For humankind it is opposite. Our evolution had led to a very generalized ability. Our highly developed intelligence and ability to make and handle tools mean that we can do almost anything. Humans evolved in such a way that we are able to move into every environment on Earth and even into space. No natural competitor offers great resistance, and other natural enemies such as disease have been controlled.

Said another way, we see in humankind a great imbalance between biological potential and environmental resistance. The result is the rapidly increasing world population, frequently referred to as the population explosion. Further, to support our growing population, natural ecosystems are being increasingly displaced by human habitations, agriculture, and other human supporting activities.

小题1:From the passage we can infer that in the course of evolution _______.

A．humankind is very important to earlier species, such as the primate group

B．human beings are limited by the environment while animals are not

C．human beings become more and more different from each other

D．humankind has experienced a generalization rather than specialization in ability小题2:According to the passage, primate includes such animals as _______.

A．monkeys and anteaters

B．tigers and apes

C．apes and monkeys

D．monkeys and giraffes小题3:According to the passage, evolution has made it possible for humans to _______.

A．increase the population

B．resist natural offers

C．go to the moon

D．cure all diseases小题4:According to the author, imbalance between biological potential and environ mental resistance has resulted in _______.

A．the population explosion

B．the destruction of human habitations

C．the growth of natural ecosystem

D．the specialization of humans

Students and Technology in the Classroom

I love my Blackberry—it’s my little connection to the larger world that can go anywhere with me．I also love my laptop computer，as it holds all of my writing and thoughts．Despite this love of technology, I know that there are times when I need to move away from these devices（设备） and truly communicate with others．

On occasion, I teach a course called History Matters for a group of higher education managers．My goals for the class include a full discussion of historical themes and ideas．Because I want students to thoroughly study the material and exchange their ideas with each other in the classroom, I have a rule —no laptops, iPads, phones, etc．When students were told my rule in advance of the class, some of them were not happy．

Most students assume that my reasons for this rule include unpleasant experiences in the past with students misusing technology．There’s a bit of truth to that．Some students assume that I am anti-technology．There’s no truth in that at all．I love technology and try to keep up with it so I can relate to my students．

The real reason why I ask students to leave technology at the door is that I think there are very few places in which we can have deep conversations and truly engage complex ideas．Interruptions by technology often break concentration and allow for too much dependence on outside information for ideas．I want students to dig deep within themselves for inspiration and ideas．I want them to push each other to think differently and to make connections between the course material and the class discussion．

I’ve been teaching my history class in this way for many years and the evaluations reflect student satisfaction with the environment that I create．Students realize that with deep conversation and challenge, they learn at a level that helps them keep the course material beyond the classroom．

I’m not saying that I won’t ever change my mind about technology use in my history class, but until I hear a really good reason for the change, I’m sticking to my plan．A few hours of technology-free dialogue is just too sweet to give up．

小题1:Some of the students in the history class were unhappy with______．

A．the course material

B．others’ misuse of technology

C．discussion topics

D．the author’s class regulations小题2:The underlined word “engage” in Para．4 probably means ______．

A．explore

B．accept

C．change

D．reject小题3:According to the author, the use of technology in the classroom may ____．

A．keep students from doing independent thinking

B．encourage students to have in-depth conversations

C．help students to better understand complex themes

D．affect students’ concentration on course evaluation小题4:It can be inferred from the last paragraph that the author ______．

A．is quite stubborn

B．will give up teaching history

C．will change his teaching plan soon

D．values technology-free dialogues in his class

下列分子的电子式书写正确的是[ ]

A．氨 

B．四氯化碳 

C．氮气

D．二氧化碳

开关站常用作变电站10kV母线的延伸，担负着接受和重新（）10kV出线的作用。

A.分开

B.分段

C.分析

D.分配

(21) 不是复杂指令系统计算机(Complex Instruction Set Computer，CISC)的特征。

A．丰富的寻址方式
B．多种指令格式
C．指令长度可变
D．设置大量通用寄存器