5. They are cheaper than usual.
它们比平常便宜些。
还能这样说：
They are sold in lower price than usual.
The price is less than usual.
应用解析：
as usual 如往常一样，照例

6. Today, I'd like to show you something which I'm sure you'll find interesting.
今天我要向你们展示一些东西，我相信你们会感兴趣的。
还能这样说：
Today, I will show you something which you must feel interested in.
I will display you something which may attract you today.
应用解析：
There is something in the wind.
好像要发生什么事了。

7. This is sold by set, not by piece.
这是按套出售的，单件不卖。
还能这样说：
We don't sell the single product.
It is sold by set instead of by piece.
应用解析：
give sb. piece of one's mind 责备某人；
pick theory to pieces 把某理论贬得一钱不值

8. We've only had three orders all morning!
我们一上午仅接到3份订单！
还能这样说：
Only three orders come to us in the morning.
All morning we only receive three orders.
应用解析：
advance in close order 以密集队形前进；
in good order 情况正常；有条不紊；
large order 难以满足的要求