1. Why don't we think of things that our classmates want to buy?
Why don't we（you）+do …？= Why not + do…？
Why not go and see her?
How about（What about）
Shall we do…？ Let's do… We'd better do…等 例：
Why not go shopping this Sunday?
Let's go shopping this Sunday.
Shall we go shopping this Sunday?
How （What）about going shopping this Sunday?
2. Suddenly, Danny hears somebody say something.
在感官听觉动词see, watch, notice, look at, hear, listen to等词后，用省略的to的动词不定式作宾语补足语。当变成被动语态时，要恢复to。例：
We often heard them argue next door.
I saw him walk into the headmaster's office.
He was noticed to come in the room.
3. Sometimes, business English is hard to understand.
To understand business English is hard. 或
It is hard to understand business English.
The instructions are easy to follow.
It's easy to follow the instructions.
To follow the instructions is easy.
4. How much does it cost?
此句是用来寻问价钱的，还可以用what's the price of来表示。 How much does your coat cost?
What's the price of your coat?
5. I don't think it would be safe to do my homework on a bicycle. 我认为骑在自行车上写作业不是安全的。
It was fun to sell the cookies.
It is + n. /adj + to do. 意为做某事如何……例：
It is fun to learn English.
It's not good to speak when you have meals.
6. To hold up posters, maps and other papers.
动词不定式做目的状语。动词不定式作目的状语时，可以将其放于句首，也可以放于句末。例： To learn English well, he went to England.
（He went to England to learn English well.）
7. He made his first push-pins by himself.
makesth. by oneself 独自做……，可以表示为：
He made his bed by himself（alone）
8. The Moore family still owns the company and… 。
owner n. "拥有者，物主"。例：
The owner of the house is Li.
Li owns the house.
own还可以作形容词，意为"自己的"，常和形容词性物主代词连用，例： This is our own room.