根据括号内所给动词的适当形式填空，必要时可加助动词。

     In some foreign countries,some people 1            (do, not) like the number 13. They don't think 13 is a

lucky number.

     Michael 2            (have) the same idea Today is his twentieth birthday. He 3            (ask) some friends

to his birthday party. All of his friends 4             (arrive) at his home at seven. So he asks them 5           

(sit) around the dinner table. He begins to count the number of the people. Suddenly, he says Oh, there 6            (be) thirteen people here! Everyone is unhappy, but Mr Brown isn't, He says slowly, 7            

(do not) worry, my dear friends! We have fourteen people here because my wife Mrs Brown will 8            

(have) a baby in a few weeks. All of them become happy again.Congratulations! they 9            (say) to Mr

and Mrs Brown.Then they 10            (enjoy) the nice food and have a good time.

在有限的空间急剧燃烧就会产生爆炸．

（1）某炼油厂310号油罐泄漏，一辆拖拉机行驶至附近，随着轰的一声巨响，瞬间油罐起火爆炸，后经及时扑救，大火终于扑灭．可十几支消防水龙头对周边油罐继续喷水6小时，事隔三天，市环保部门对炼油厂和市区上空大气进行监测，其污染指标均未超过国家有关标准，试依据学过的化学知识回答：

①3lO油罐起火原因______．

②火灭后继续对周边油罐喷水的原因______．

③市环保部门要检测大气中的有害气体有______．

（2）爆炸会给人类带来巨大的灾难和损失，但在受到控制的条件下，它也可以为人类服务．

在采煤工业上，把干冰与炸药放在一起，既能增强爆炸威力，又能防止火灾．试分析能增加爆炸威力的原因是______；能防止火灾的原因是______．