现在的教室作为标准化考场，都安装了如图所示的电子监控器，其主_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题选择题

现在的教室作为标准化考场，都安装了如图所示的电子监控器，其主要由光学系统和光电转换系统两部分组成。光学系统收集监控区域内的景物信息，经光电转换系统转换成电信号并输送到监控中心。其中光学系统的工作原理是利用（）

A．平面镜成实像

B．平面镜成虚像

C．凸透镜成实像

D．凸透镜成虚像

答案

答案：C

题目分析：电子监控器的镜头实际上是一个凸透镜，其成像原理是照相机的成像原理是相同的，成倒立、缩小的实像．

故选C．

点评：凸透镜成像的三种情况和应用是凸透镜成像习题的重要依据，一定要熟练掌握．

单项选择题

糖尿病肾病的微量白蛋白尿期，尿中自蛋白排泄率为（）。

A.20～200μg／min

B.<20μg／min

C.>200μg／min

D.>30μg／mm

E.>3.5克／24小时

完形填空

Some people will do just about anything to save money. And I am one of them. My family’s last vacation was a good         to prove it. It was my six-year-old son’s winter break from school, and we were         home from Fort Lauderdale after a week-long trip. The flight was        , and Delta, the airline, offered us $400 per person in credits to give up our seats and leave the next day. I had meetings in New York, so I had to        . But that didn't mean my husband and my son couldn't stay. I took my nine-month-old and took off for home.
The next day, my husband and son were offered more         to take an even later flight. Yes, I encouraged — okay, ordered — them to wait it out at the        , to "earn" more Delta Dollars. Our total take: $1,600. Not bad, huh?
Now some people may think I'm a bad mother and not such a great wife either. But as a big-time bargain hunter, I know the value of a        . And these days, a good deal is something few of us can afford to        .
I've made living looking for the best deals and         the worst tricks. I have been the consumer reporter of NBC's Today show for over a decade. So far, I feel proud that I have written a couple of         including one titled Tricks of the Trade: A Consumer Survival Guide. And I really do what I         in.
I tell you this because there is no         in getting your money’s worth. Honestly, I’m also         when it comes to shoes, clothes for my children, and expensive restaurants. But I wouldn't hesitate to spend on a good haircut. It keeps its shape longer, and it's the first thing people        . And I will also spend on a classic piece of furniture.         lasts.

B．overcrowded

D．overpowered

A．dictionaries

B．tightfisted

A．Satisfactory