从运行的“目标”上比较农业生态系统和自然生态系统。

产后血晕的病因病机有虚实两端，虚者由____，实者则为____。

My mind seems always to return to the day when I met Carl. The city bus stopped at a corner to pick up the daily commuters (someone who travels regularly to and from work), a group in which I was included. Boarding the bus, I looked for a place to sit. At last, I found a place near the back.

The man in the seat next to the one I was going for was an older man in a grey suit, well-worn dress shoes, and a black hat like I always pictured reporters wearing, but without the little press card. Seated, I began to read the book I had been carrying, which was Jack Kerouac’s On the Road. The man in the seat next to me introduced himself by asking if I had read any other book like the one I was holding. When I told him I had, he seemed to become interested, and so did I. He introduced himself as Carl and asked if I liked jazz, and I told him that I didn’t really listen to it, and that I liked rock and roll. Waiting for Carl to tell me that I should listen to real music, I was shocked when he just smiled and nodded. He said, "You remind me of myself when I was your age. I remember how my parents hated jazz and how they couldn’t see how I could listen to that awful noise. I bet your parents say the same thing, don’t they?" Now it was my turn to smile, amused with how right he was.

As the bus carried us from one side of the city to the other, Carl and I talked about a lot of different things. The more we talked, the more amazed I became at how much the two of us really had in common, despite the age difference. I haven’t seen him since we parted, but the thought of our connection that day rarely leaves my mind.

Carl really made me think about how much we can learn from each other if we just break through the blocks between us we’ve got. I mean, I would have never thought before that day that I could have anything in common with someone so much older than I. But Carl taught me that no matter what we are, we are all just people, and that we should make an extra effort to try and get to know our neighbors and people we see every day, regardless of age, race, religion, sex, or anything else. If we all take the time to attempt to understand each other, I think that the world would be a much better place that we could share together, as humans.

小题1:From the first paragraph we know that the author _____________.

A．did not mind whether there was a seat or not

B．hoped to have a seat when getting on the bus

C．thought the bus was overcrowded

D．looked for a seat but failed小题2:The author usually imagined a reporter as one who _____________.

A．liked jazz music

B．enjoyed talking with others

C．liked reading Jack Kerouac’s works

D．usually wore a black hat and press card小题3: After talking with Carl, the author realized that _____________.

A．older people were nice to talk to

B．he should have known Carl earlier

C．his parents were so different from Carl in listening to music

D．age was not necessarily a problem in heart-to-heart communication小题4:It can be inferred from the passage that _________.

A．the author hasn’t seen the old man since then

B．jazz music used to be more popular than rock and roll

C．the author was not satisfied with human relationships in the world

D．Carl made the author realize we humans live in peace and brotherhood

“温室效应”是全球关注的环境问题之一．CO₂是目前大气中含量最高的一种温室气体．因此，控制和治理CO₂是解决温室效应的有效途径．

（1）下列措施中，有利于降低大气中CO₂浓度的有______（填字母）．

a．减少化石燃料的使用               b．植树造林，增大植被面积

c．采用节能技术                     d．利用太阳能、风能

（2）许多化学物质是一柄“双刃剑”，对CO₂的利弊评价不妥的是______（填字母）．

A．大气中CO₂过多会造成“温室效应”

B．“碳酸水”浇灌植物对植物光合作用、改良碱性土壤有利

C．利用干冰可进行人工降雨

D．大气层中CO₂越多，抵御紫外光作用越强

（3）某学生用下图装置进行“绿色植物光合作用”的探究实验．先将甲、乙两个装置同时放在黑暗处一昼夜，然后一起放到阳光下．几小时后检验：甲装置中植物的叶片有淀粉生成，而乙装置中植物的叶片却没有淀粉生成．

则：乙装置中盛放氢氧化钠溶液的目的是______，写出相应的化学方程式______．

启动机正常启动不转动，用起子将附加继电器上的“点火”、“电池”接柱短路，启动机运转正常，则表明（）有故障。

A、点火开关

B、磁力开关

C、电枢绕组

D、励磁绕组

安全带要（），注意防止摆碰撞。

A.低挂高用

B.高挂低用

C.缓冲器

D.监护