问题 解答题

如图为显微镜的构造图.

(1)了解它的结构与功能,完成下列各题(括号内填标号):

①有成像功能的结构是[______]______、[______]______.

②对光时,在做好准备步骤的基础上,再转动[______]______,使光线经通光孔反射到镜筒内,从[______]______可以看到白亮的圆形视野.

③转动时使镜筒升降幅度大的结构是[______]______,在观察时要与低倍物镜还是高倍物镜配合使用?______.

(2)在用显微镜做观察实验时,若发现视野有一个黑点,你是如何确定其所在部位的?请指出你的探究方法.

答案

(1)①光学显微镜是根据凸透镜的成像原理,要经过物镜、目镜(凸透镜)的两次成像,因此有成像功能的结构是[①]目镜、[④]物镜.

②对光的方法是:转动粗准焦螺旋,使镜筒上升;转动转换器,使低倍的物镜对准通光孔;转动遮光器,用较大光圈;左眼注视物镜,有眼睁开,转动[⑩]反光镜,直到[①]目镜看见白亮的视野.

③我们在使用显微镜时应先使用低倍镜观察,然后再选用高倍镜观察.低倍镜视野大,物镜倍数越低,镜头越短,物镜与玻片标本的距离越远,因此转动粗准焦螺旋观察时,不容易碰到玻片标本,先使用低倍镜能够迅速地找到所要观察的物像,然后再用高倍镜的话就很容易找到物像了.转动时使镜筒升降幅度大的结构是[⑨]粗准焦螺旋,故在观察时要与低倍物镜配合使用.

(2)解答此类题主要通过转动目镜、玻片标本配合判断.移动玻片时,若黑点也随着移动,则黑点在玻片上;若黑点不移动,再转动目镜,黑点也转动,则黑点在目镜上;若黑点不转动(或转动转换器,换用物镜,黑点消失),则黑点在物镜上.

故答案为:(1)(6分)①目镜                 ④物镜

⑩反光镜               ①目镜

⑨粗准焦螺旋           低倍物镜

(2)(3分)移动玻片,若黑点也随着移动,则黑点在玻片上;若黑点不移动,再转动目镜,黑点也转动,则黑点在目镜上;若黑点不转动(或转动转换器,换用物镜,黑点消失),则黑点在物镜上.

不定项选择
阅读理解

Toyota Motor Corp, Japan’s biggest carmaker, said on Friday it will recall 1,489 Lexus sedans (高级轿车) sold in China. "It will take us some time to ship the fuel tanks and vent pipes to China to change those in these Lexus sedans for customers free of charge, if problems are found," said Yang Hongjian, a spokes- woman of Toyota’s China representative office.

The expected recall will affect Lexus LS430 sedans made in Japan from July 29, 2003 to January 14, 2004, the repre­sentative office said in a statement. Toyota has not received complaints from Chinese customers, according to the state­ment. The move will be part of Toyota’s global recall of 18,200 Lexus LS430s. It will be the third car recall in China in two weeks. Although automobile recall is a common prac­tice in developed markets, it remains new to Chinese customers. The Chinese government published long-awaited automo­bile recall rules on March 15, which will be officially carried out at the beginning of October.

China’s auto market is forecast to reach 10 million units by 2010. Automakers, especially Chinese producers, will face greater pressure from automobile recalls, which could be very costly sometimes, and should be in full preparations, accord­ing to the expert. The Japanese carmaker sold 1, 549 Lexus vehicles on the Chinese mainland during the first five months of this year, according to Yang. Lexus sales on the mainland reached 4,000 units last year, up from 1,600 units in 2002. (China Daily July 3, 2004)

1. What can we learn from the text?

A. Chinese customers are not satisfied with Toyota Lexus LS430 sedans.

B. Chinese car market has seen car recalls three times so far.

C. Toyota will have a worldwide recall of Lexus LS430 sedans.

D. Toyota Motor start to recall Lexus Sedans due to the problems with fuel tanks.

2. The carmakers were unwilling to recall their cars in the past mainly because ______.

A. they were not fully prepared

B. they couldn’t afford the cost for their car recalls

C. their products could not meet the required standard

D. there were no related rules and little pressure

3. It is implied in the passage that ______.

A. sales of homemade automobiles will grow even faster

B. automobile recalls will take place in China more fre­quently

C. China’s car market is forecast to be the biggest by 2010 in the world

D. Toyota is likely to sell the most Lexus Sedans in China in the future

4. Which of the following is the best tide of this passage?

A. Toyota to Recall Its Lexus Sedans Sold in China

B. China Prepares to Recall Cars

C. The Problems in China’s Car Market

D. Costly Japanese Car Recalls