Question

英文句子改错，急

After he visiting the town, many things have changed.
这句话是否正确？有错请指出，并说明为什么错？
此处应用after did sth还是用after doing sth？为什么？

Answer 1

after改为since，从句为过去时，主句为现在完成时，连接词是since。还可以把 have changed 改为changed，连接词还是after.
1．主句用一般现在时，从句可用任意时态。可归纳为“主现从不限” 。2、主句用过去时，从句用过去某个时态。可归纳为“主过从四过”。3、主句用过去时，从句是科学真理、客观常识、名人格言时用一般现在时。4、情态动词could/would用于，“请求”，表示委婉、客气的语气时，从句不受主句的约束。根据从句语法功能的不同可分为：主语从句、表语从句、宾语从句、同位语从句、定语从句和状语从句6类。前四类由于主语从句、表语从句、宾语从句及同位语从句在句子的功用相当于名词，所以通称名词性从句；定语从句功能相当于形容词，称为形容词性从句。而状语从句功能相当于副词，称为副词性从句。状语从句还可以分为条件状语从句、原因状语从句、地点状语从句、目的状语从句、让步状语从句、比较状语从句、方式状语从句、结果状语从句和时间状语从句。

Answer 2

After he visiting the town, many things have changed.的错误包括主句动词时态和After he visiting这个莫名其妙的短语（既不是从句，又不是正常短语，还不是独立主格结构）。
1.since和after都可表示：在...之后，但区别很大。
2.since
（1）since+过去一个时间点（如具体的年、月、日期、钟点、1980，last month，half past six）。
（2）since+一段时间+ago.
例如：I have been here since five months ago. 我在这儿，已经有五个月了。
（3）since+从句。
例如：Great changes have taken place since you left. 你走后，变化可大了。
Great changes have taken place since we were here.我们走后，变化可大了。
（4）It is+一段时间+since从句。
例如：It is two years since I became a postgraduate student. 我考上研究生有两年了。
3.after
after表示“在……之后”，并不表示持续到现在，可能是指时间点，也可能是一个时间段（可能持续到现在也可能不持续到现在，after 并不作任何暗示）。after后面加一段时间，时态是过去(完成)时，将来时：比如：
He became quarrelsome after drinking too much. 他喝醉了就要找人吵架。
She went off in a huff after losing the game. 她输了比赛，气呼呼地走了。
Three athletes were sent home after failing drugs tests. 3 名运动员因未通过药检被遣送回国。
I had terrible pain in my guts after eating too many plums. 我李子吃得太多了，肚子疼得厉害。
he went (has gone)to Paris after 2000.2000年后他去了（或已经去了）巴黎。
2.根据since和after的上述区别，建议改写如下。
（1）After his visiting the town, many things have changed.
（2）After he visited the town, many things have changed.
（3）After he visited the town, many things changed.
（4）Since his visiting the town, many things have changed.
（5）Since his visited the town, many things have changed.

Answer 3

1. 有错：visiting使用不当！

①如果逗号前用从句作状语，应该用一般过去时after he visited the town.

②如果逗号前用短语作状语，则应该表达成after his visit to the town.

不论是①、②哪种情况，visiting在此处都是不能用的。

2. 后半句用来表达“已经发生了很多变化”，使用一般现在完成时many things have changed是没有任何问题的。

追问

语法太难了，我不太明白从句指的是哪句？短语指的是哪个？为什么从句作状语要用过去式，用短语作状语要用不定式？能否解释更详细一点，还是不太明白前因后果，为什么visiting不能用？那它在什么情况下能用？

Answer 4

你好！
原句中的he改为his 。
原句改为：
After his visiting the town,many
things have changed.
his visiting the town 是动名词的复合结构作介词after 的宾语。
动名词复合结构的构成：
形容词性物主代词或名词的所有格＋动名词
例：I insist on Tom’s going there.
Tom’s going there 作insist on 的宾语。

Answer 5

After he visited the town, many things changed.

after后的从句谓语是过去式；所以，主句时态也应该用一般过去时。
或者(after...属于过去）
After his visiting the town, many things changed.
或者
Since he visited the town, many things have changed.