（1）The following items totaling $4000 are still open on your account.
你的欠款总计为4000美元。
（2）It is now several weeks since we sent you our first invoice and we have not yet received your payment.
我们的第一份发票已经寄出有好几周了，但我们尚未收到你的任何款项。
（3）I'm wondering about your plans for paying your account which,as you know,is now over 40 days ast due.
我想了解一下你的.付款计划，要知道，你的付款已经逾期40多天了。
（4）We must now ask you to settle this account within the next few days.
请你务必在这几日内结清这笔账款。