四冲程发动机曲轴转二周,活塞在气缸里往复行程()次,进、排气门各开闭()次,气缸里热能转化为机械能()次。
参考答案:2.4;1
用化学方程式表示如下化学原理.
(1)用稀盐酸除去生锈的铁钉(铁锈的主要成分是Fe2O3)______.
(2)用胃舒平主要成分是Al(OH)3治疗胃酸过多症______.
(3)用AgNO3溶液鉴别假矿泉水中含有少量稀盐酸______.
(4)用硝酸钡溶液滴入稀硫酸中制取少量硝酸______.
句子翻译(共5小题;每题2分;每空1词,每词1分;满分10分)
小题1:当搬到一个新的地方,我们通常需要让自己去适应新的环境。
When we move to a new place, we usually need to _________ _________ to the new surroundings.
小题2:在现代社会,既要具有竞争力又要具有合作精神对于我们来说才是明智的。
In modern society, it does _________ _________ for us to be both competitive and cooperative.
小题3:在某种程度上来讲,我们是否能向后代提供一个更美好的明天取决于我们今日的行为。
To some extent, whether we can present a better earth to our future generations _________ _________ what we are doing today.
小题4:现在中国政府正竭力加速构筑一个和谐的社会
Nowadays, the Chinese government is trying its best to _________ _________ the construction of a harmonious society.
小题5:考虑到他还年轻,他父母不同意他明年出国读大学。
Considering his young age, his parents haven’t _________ _________ his going abroad for college education next year.