3．2. 3 Exercises练习
Ⅰ．Sentence translation．
1．The boy student was criticized yesterday morning．
2．The compass was invented by Chinese long ago．
3．Such books are written for children．
4．This help-the-poor policy has been successfully carried out．
5．Sometimes the communication would be seriously disturbed by solar spots．
6．A railway bridge is being built by the workers．
7．Mechanical energy can be changed back into electrical energy through a generator．
8．You are wanted on the phone．
9．He was considered quite qualified for the job．
10．Visitors are requested to deposit their bags before entering the exhibition hall．
11．Life cannot be understood without much charity．
12．Measures have been taken to prevent the epidemic from spreading quickly．
13．Attention should be paid to safety in handling exploders．
14．The price of tape recorders has been cut again．
15．That city is well supplied with water．
16．This limousine will be equipped with safety belts．
17．Shelley＇s poems have been translated into many languages．
18．It is stressed that the field of science may be divided into two major areas: natural science and social science．
19．It should be pointed out that this process is oxidation．
Ⅱ．Passage translation．
The protons and neutrons in the nuclei of most common atoms are strongly held together．The nuclei of these atoms are said to be stable．On the other hand，the nuclei of some atoms especially the bigger ones like uranium，are not so stable．This is partly due to the large number of protons and neutrons present in their nuclei．
Large unstable nuclei have a tendency to break up，on their own，into small nuclei．They can also be made to break up，or split，into smaller nuclei if they are bombarded with very small particles．The splitting of the nucleus of an atom is called fission．But what is the importance of fission？When fission of，say，a uranium nucleus occurs，the nucleus splits up into small nuclei of other atoms and gives off neutrons and a large amount of nuclear energy in the form of heat．The energy given off from the fission of just one kilograms of uranium is equivalent to the energy we can obtain from burning over 900，000 kilograms of coal! Just imagine what a tremendous amount of energy we can get from nuclear fission．