求付款条款怎么写

英文的付款条款可以写成：

Payment Terms:
1. 50% of the total invoice amount shall be paid within 7 days upon receipt of the copy of the bill of lading.
2. The remaining 50% shall be paid within 20 days upon receipt of the bill of lading.

请注意，这只是一个示例，具体的付款条款应该根据双方的协商和具体情况来确定。