正常人的眼睛观察25厘米处的物体最清楚,眼睛也不容易感到疲劳,若要使眼睛的像成在

题型:填空题

问题:

正常人的眼睛观察25厘米处的物体最清楚,眼睛也不容易感到疲劳,若要使眼睛的像成在距离眼睛25厘米处,眼睛与平面镜的距离应为_____________。

考点:平面镜成像的特点和原因
题型:填空题

单代号网络计划的节点符号可以表示( )。

A.工作时间

B.工序代号

C.工序代号与工作时间

D.均不表示

题型:填空题

I was a single parent of four small children, working at a low paid job. Money was always tight, but we had a (1) over our heads, food on the table, clothes on our backs, and if not a lot, always (2) . Not knowing we were poor, my kids just thought I was (3) . I’ve always been glad about that.

It was Christmas time, and although there wasn’t (4) for a lot of gifts, we planned to celebrate with a family party. But the big (5) for the kids was the fun of Christmas (6) .

They planned weeks ahead of time, asking (7) what they wanted for Christmas. Fortunately, I had saved MYM120 for (8) to share by all five of us.

The big (9) arrived. I gave each kid a twenty-dollar bill and (10) them to look for gifts of about four dollars each. Then everyone scattered. We had two hours to shop; then we would (11) back at the "Santa’s Workshop"

Driving home, everyone was in high Christmas spirits, (12) my younger daughter, Ginger, who was unusually (13) She had only one small, flat bag with a few candies—fiftycent candies I was so angry, but I didn’t say anything (14) we got home. I called her into my bedroom and closed the door, (15) to be angry again. This is what she told me.

"I was looking (16) thinking of what to buy, and I (17) to read the little cards on the ’Giving Trees’. One was for a little girl, four years old, and all she (18) for Christmas was a doll. So I took the card off the tree and (19) the doll for her. We have so much and she doesn’t have anything. "

I never felt so (20) as I did that day.

18().

A.since 

B.after 

C.while 

D.until

题型:填空题

下列关于城市的集聚性的论述中,不正确的是( )。

A.城市是人类财富集中的区域,中外的古代战争莫不以攻占城池、洗劫城市财富作为其显著特征之一,现代城市更是财富集中地域

B.城市是人类科学文化的集中地域。城市中集中着人类的绝大部分的科研机构、大学以及文化机构,其科学文化功能是任何其他人类生存地域所无法比拟和不能代替的

C.城市生态系统中,分解者的稀缺以及部分代替分解者职能的处理设施的不足,更使城市运转过程中产生的废物难以如同自然生态系统中那样得到有效的分解。相反,这些废物却积淀和滞留在城市及附近地域,给城市带来极大的负面作用

D.城市是交通集聚之处。在城市里,铁路、公路、航空设施高度汇集,为城市生产和生活提供便利。此外,城市也是建筑、能源、生产、消费的中心

题型:填空题

光电式光量传感器(实为硫化镉光敏电阻)的特性是:周围变暗时,其电阻()。

题型:填空题

简要病史:男性,60岁,肢体关节疼痛半年。答题要求:请围绕以上简要病史,口诉该患者现病史及相关病史应询问的内容。

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