关于付款方式，请帮我翻译一下句子

About the payment terms, we only accept the irrevocable L/C draft at sight and the irrevocable usance L/C 30 days after the date of shipment for large quantities. we will send the sample to you asap if you agree with the above-mentioned terms. Furthermore,pls pay us 50% sample charges in advance for both sincere cooperation.

note:即期信用证是见单即付，没有“最多不超过30天期限”这种说法的，一旦这样表述，那就指的是远期信用证了。还有信用证要加上“不可撤消”，表述明确。

As per the payment terms, we only can accept L/C within 30 days according to the large quantity order. If you can accept this payment terms, we can send out the sample asap. Hereby pls arrange 50% of
the sample charge to express your sinceretity.

About the payment, we only accept L/C at sight. If your order is large quantity, no later than 30 days. Hope you can kindly accept this, then we will arrange to send you the sample. Also please pay half of the sample fee for our further cooperation.Thanks a lot.

我不是高人，我尽力而为 ：）

是商务英语作业吧
As the