Question

短文填空。根据课文原意填出空缺的单词。

     Metals are very important, so when using them we should know how they react with different  1 .
Take iron used in electrical   2   for example, when heated in   3  , it will react slowly. When it is put
together with water or  4  , there will be a    5  reaction.

Answer 1

1. substances   2. equipment  3. oxygen    4. steam    5. partial