1.I live in a very old town which is surrounded by beautiful woods. 我住在一个由美丽的树林环绕的古老的小镇上。
这是一个主从复合句，which is surrounded by ... 为定语从句，修饰town。which 指代 town 。从句用的是被动语态，“被......所包围”，如果将从句独立为一个句子，则为：My town is surrounded by beautiful woods.
2. on Sundays 是泛指“在星期天”，而不是指在某个星期天。
3.hundreds of people，数以百计的(游)人。
hundreds of people 复数形式表概数，“数以......计的”与 of 连用，作名词的修饰语，其后面的名词必然是复数形式。
4. . . . to see our town and to walk through the woods. 来参观我们的小镇并在树林中散步。
to see our town and to walk through the woods 为不定式短语作目的状语。
这里用 and 连接的两个动词不定式。介词through，“穿过”，强调纵深向，如：walk through the forest 穿过森林：而 across 强调横向，如：
walk across the street 横穿街道
5.Visitors have been asked to keep the woods clean and tidy.游客已被告知要保持树林的整洁。
现在完成时的被动语态，说明需求的行为应为游客所知。(句中 have been asked是被动语态的完成时结构。详见本课语法部分。)to keep the woods clean and tidy 是动词不定式短语，作主语visitors的补足语。clean and tidy 是宾语 the woods 的宾语补足语。
clean and tidy 表示“整洁的，清洁的”这是英语中的常用结构，其它常见的类似结构还有：black and blue 青一块紫一块;happy and gay 高高兴兴
heart and soul 全心全意，一心一意
6.go for a walk，去散步。
7.What I saw made me very sad.我所见到的一切使我非常难过。
句中的主语 What I saw 是 what 引导的名词性从句(主语从句)。例如：
What the little boy did surprised his mother. 那个小男孩所做的一切使他母亲十分惊讶。
What you do makes me happy. 你所做的是我愉快。
8. The litter baskets were empty and ground was covered with pieces of paper，cigarette ends，old tyres，empty bottles and rusty tins.
句中 and 连接的并列句，“the litter baskets were empty” 与“groun was ... 分别为两个并列分句，be covered with ... 被 ...... 覆盖。如：
The desks are covered with dust. 桌子上布满了灰尘。
The ground was covered with snow. 地上覆盖着雪。
9. Anyone who leaves litter in these woods will be prosecuted!凡在此树林里丢垃圾者，将依法处置。
这是一个主从复合句，who 引导定语从句，修饰先行词anyone 。will be prosecuted 为将来时的被动语态。
Anyone who comes to the party is welcome. 该晚会来者不拒。
Anyone who breaks the traffic regulations will be fined. 任何违反交通规则的人都会被罚款。
新概念英语第一册143-144课文详注语法知识点 Grammar in use
(1)现在完成时形式： has/have + been + 过去分词：
The basket has already been emptied. 篮子已经被腾空了。
They have already been invited. 他们已被邀请。
(2)一般将来时形式： will/shall +be +过去分词：
The floor will be swept soon. 地不久就会扫的。
The knives will be sharpened soon. 刀不久就会磨的。
新概念英语第一册143-144课文详注词汇学习 Word study
He placed the record back to the shelf.
Their request placed me in a difficult position.
The company has placed him with a branch office in Tokyo.
There is no better way to place the homeless children.
Trespassers will be prosecuted.
They prosecuted him for shoplifting.
We are going to prosecute the investigation further.
The beautiful white house is surrounded by green trees.
That old professor loved to surround himself with young people.
When I went into the room, I saw Tim sitting on the floor surrounded by boxes.
新概念英语第一册144课课后练习答案 Key to written exercises
1 The writer lives in a very old town which is surrounded by beautiful woods.
2 Because it is a famous beauty spot.
3 Visitors have been asked to keep the woods clean and tidy.
4 Litter baskets have been placed under the trees.
5 The writer went for a walk in the woods.
6 Yes, he saw a lot of rubbish.
7 He saw a sign among the rubbish.
8 The sign said, ‘Anyone who leaves litter in these woods will be prosecuted.
1 Someone has aired it. It has already been aired.
2 Someone has cleaned them. They have already been cleaned.
3 Someone has emptied it. It has already been emptied.
4 Someone has sharpened it. It has already been sharpened.
5 Someone has turned them on. They have already been turned on.
6 Someone has bought them. They have already been bought.
7 Someone has swept it. It has already been swept.
8 Someone has taken them to school. They have already been taken to school.
9 Someone has invited them. They have already been invited.
10 Someone has told them. They have already been told