5. We'll not pay until we see the shipping documents for the goods.
见不到货物装船单据，我们不付款。
还能这样说：
We prepare to pay when goods are received.
You can receive the payment as soon as you deliver the goods.
谚语：
The more you pay, the more you will gain.
付出越多，收获就越多。

6. Would you rather accept D/P payment terms or L/C payment terms?
您愿意接受付款交单方式还是信用证付款方式？
还能这样说：
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?
应用解析：
D/P是“document against payment”的缩写，意思是“付款交单”；
L/C是“letter of credit”的缩写，意思是“信用证”。

7. We expect payment in advance on first order.
我们希望第一次订货预付货款。
还能这样说：
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.
我听说你方会接受不同形式的付款。
还能这样说：
I heard that different kinds of payment are acceptable to you.
I heard that in your company, different kinds of payment are available.
谚语：
Every ass likes to hear himself bray.
每只驴子都爱自己叫。