中考化学知识点总结:水的化学性质
(1)分解 2H2O=通电= 2H2↑+O2...
1.主语 + was /were + 其他
2.there was /were + 其他
3.主语 + 动词的过去式 + 其他
例如:He was here just now. 他刚才在这儿。
There was an old picture on the wall last year. 去年墙上有一张旧画。
I did my homework yesterday. 昨天我做了家庭作业。
1.规则变化
(1)一般的加-ed 如:clean ----cleaned help ----helped
(2)以辅音字母+y 结尾的词变y为i再加-ed 如:study ----studied cry ----cried
(3)以元音字母+y 结尾的词直接加-ed 如: play ----played enjoy -----enjoyed
(4)以重读闭音节结尾,且末尾只有一个辅音字母的词,要双写这个辅音字母,再加-ed.
如:stop ----stopped
drop -----dropped
prefer ------preferred
2.不规则变化
go-----went
take-----took
have------had
buy-------bought
eat-------ate
see-----saw
hang------hung
meet------met
win-------won
sleep-------slept
put------put
come------came
wake------woke
read------read
do-------did
1.yesterday及其构成的短语
Tom lost his bike yesterday afternoon. 昨天下午汤姆丢了他的自行车。
2.由一段时间+ago 构成的短语
I finished my homework two hours ago. 两个小时前我就完成作业了。
3.由last +时间名词构成的短语
He went to the movie last weekend. 上周末他去看电影了。
4.由介词+过去时间的名词构成的短语
Our family lived in the country in1985. 1985年我们家住在农村。
5.其他一些时间名词或短语
I saw her just now . 我刚才看见过她
1.句中带有动词的改为疑问句时,将was /were 提到主语之前,肯定回答为”Yes ,主语(代词)+was /were ” 和”Yes, there was /were ” 否定回答为”No ,主语(代词)+wasn’t /weren’t” 和”No ,there wasn’t /weren’t”。 改为否定句时,在was /were后加not即可。
2.句中含有实义动词的,改为疑问句或否定句时,须借助情态动词或助动词did.
I know the answer.
改为疑问:Did you know the answer ?
肯定/否定回答:Yes , I did . / No ,I didn’t .
改为否定句: I didn’t know the answer.
1.表示过去的动作或存在的状态。如:
She went to Hong Kong by plane yesterday. 她昨天乘飞机去了香港。
We saw the film last week. 我们上周看了那部电影。
2.表示过去连续发生的动作。如:
Li Lei got up early in the morning , had breakfast and then went to school by bus .
李雷早上起得很早,吃过早饭,然后乘公共汽车上学。
3.表示过去一段时间内经常发生的动作。 如:
When I was at school , I always went to school by bus .
我在学校念书的时候,总是乘公共汽车上学。
一般过去时态的特殊疑问句时由“疑问词+was /were+主语+其他”或“疑问词+did+主语+其他”构成的。 如:
How did you know the result? 你是怎么知道结果的?
How many apples were there on the table? 桌子上有几个苹果?
When did he start hiccupping? 他是什么时候开始打嗝的?