8) 铝比钢的强度小得多。但如果把它和少量的铜，锰、镁等金属熔成合金，再经过热处理，就能使其达到钢的强度。

Aluminium, though much less strong than steel, can be given a strength approaching that of steel when it is alloyed with small quantities of copper，manganese and magnesium, and subjected to heat treatment processes.

9) 制造过程可以分为单件生产和大量生产。单件生产就是生产少量的零件。大量生产就是生产大量相同的零件。

Manufacturing processes may be classified as unit production with small quantities being made and mass production with large numbers of identical parts being produced.

2. 如果两个句子之间联系十分紧密，已经构成了主辅关系，英译时即可并成ー个句子。

1) 他竟会对我这样当面说慌！真是没有想到！

It never crossed my mind that she should have told me a bare-faced lie.

2) 改革价格体系关系国民经济全局，涉及千家万户。一定要采取十分慎重的态度，有计划、有步骤地进行。

As the price system reforms affected every house-hold and the national economy, they must be carried out extremely prudently in a planned and systematic way.

3) 年满十八岁的公民，都有选举权和被选举权。依照法律被刹夺选举权和被选举权的人除外。

All citizens who have reached the age of eighteen have the right to vote and to stand for election, with the exception of persons deprived of these rights by law.

4) 为了把薄的厚的金属板焊接在一起，通常采用不同的方法。这就是我们熟悉的点焊。