5. We'll not pay until we see the shipping documents for the goods.
見不到貨物裝船單據，我們不付款。
還能這樣說：
We prepare to pay when goods are received.
You can receive the payment as soon as you deliver the goods.
諺語：
The more you pay, the more you will gain.
付出越多，收獲就越多。

6. Would you rather accept D/P payment terms or L/C payment terms?
您愿意接受付款交單方式還是信用證付款方式？
還能這樣說：
Which would you prefer, D/P payment or L/C payment?
There are two kinds of payment: D/P payment and L/C payment. Which would you choose?
應用解析：
D/P是“document against payment”的縮寫，意思是“付款交單”；
L/C是“letter of credit”的縮寫，意思是“信用證”。

7. We expect payment in advance on first order.
我們希望第一次訂貨預付貨款。
還能這樣說：
Since this is our first cooperation, we hope that you can pay in advance.
Prepayment is a necessity for first order.

8. I heard you accept various kinds of payment.
我聽說你方會接受不同形式的付款。
還能這樣說：
I heard that different kinds of payment are acceptable to you.
I heard that in your company, different kinds of payment are available.
諺語：
Every ass likes to hear himself bray.
每只驢子都愛自己叫。