1）用手摸一摸已经开了一些时间的收音机，你有什么感觉？

Touch a radio which has been switched on for some time. What do you feel ?

2）人们必须通过对现象的分析和研究，才能了解到事物的本质，因此需要科学。

It is by analysing and studying the appearance of a thing that people come to know its essence. Hence the need for science.

3）内部压力越高，气体膨胀的趋向就越大，这种现象可以用提高气球温度来很好地说明。

The higher the internal pressure, the greater the tendency for the gas to expand. This phenomenon may well be illustrated with a heated ballon.

4）本工艺具有造型速度快，生产效率高，工艺性能优良，综合经济效益高，劳动条件好等优点，引起世界铸造工作者的关注。

This technology has the advantages of great moulding speed , high production efficiency, fine technological performances，excellent overall economic results and good labour conditions. Therefore, it has been taken notice of by foundry businesses all over the world. 

5. 汉语里有些句子意思的层次比较多，分开之后，译文清晰，更符合英语习惯。例如：

1）一般说来，典型的金属能导热导电，表面有光泽，具有延展性和可锻性。

General speaking , the typical metal conducts electricity and heat. It shows lustrous surface, usually with white，or so-called metallic luster. It is dustile and malleable.

2) 本文扼要地叙述了用来制造单块电路的各种工艺及其优缺点。

The various processes which may be used in fabricating a monolithic circuit are briefly reviewed . The advantages and disadvantages of each process are enumerated.

3) 耳朵是用来听声音的器官，鼻子用来嗅气味，舌头用来尝滋味。

The ear is the organ which is used for hearing. The nose is used for smelling. The tongue is used for tasting.