Different metals have different uses.When we use metals,it is important to know how they react with different 1. (substance).The 2. (react)of metals with these substances can 3. (put)in order.From the table,we can find that potassium(钾)reacts most with water 4. copper doesn’t react with water.When we heat calcium in oxygen,it 5. (burn)to form an oxide.
In 6. second part of the experiment,you must boil the water 7. (make)sure there is no air in it.You add some oil to the water 8. this keeps air out of it.It also shows that iron doesn’t rust in water 9. air in it.However,the nails rust in the tube with ordinary water in the third part of the experiment.
That is 10. iron reacts with air and water.
答案
1.substances 考查名词单复数。substance为可数名词,且被different修饰,因此应用复数形式。
2.reaction 考查词性转换。the后应用名词形式。
3.be put 考查被动语态。reaction与put之间为被动关系,故用被动语态。
4.while 考查连词。此处表示对比,故用连词while。
5.burns 考查动词的时态。此处陈述的是客观事实,主语为it,因此用动词的第三人称单数形式。
6.the 考查冠词。序数词前应用定冠词the。
7.to make 考查非谓语动词。此处动词不定式短语作目的状语。
8.because 考查状语从句。句子前后为因果关系,故应用because引导原因状语从句。
9.without 考查介词。此处表示“没有”,故用介词without。
10.how 考查表语从句。此处表示方式,故用how。
