1. You will receive a discount by ordering today.
今天下訂單的話有折扣。
還能這樣說：
We will discount the product if you make an order today.
We'll give you a discount if you make a large order today.
應用解析：
on order 定購中（發貨而尚未交貨）；
on the order of 屬于……一類的，與……相似的

2. We are glad to receive your order and confirm our acceptance for it.
我們很高興接到你的訂單并且確認可以接受。
還能這樣說：
We are pleased to have your order and it is certain to be accepted.
We make it certain that we can accept the order which we are pleased with.
諺語：
Glad children make glad parents.
孩子好，父母笑。

3. Your order can go out next Monday.
你的訂單下周一就可以出貨。
還能這樣說：
Your order can be sent next Monday.
Next Monday, you can have the receipt of the order.
諺語：
Out of the (frying) pan and into the fire.
跳出鍋里，掉進火里。

4. The trouble is that the factory is running at full capacity.
問題是公司的訂單已經滿了。
還能這樣說：
The problem is that the order is full.
What matters is that the factory is fully engaged.
應用解析：
full of admiration 懷著欽佩的心情；
full of the roof （旅館等）住滿了人的；
full to 滿到……；
full life 有豐富經歷的一生