1、We usually precontract with the suppliers to ensure timely delivery of the materials.
我们通常与供应商进行预先合同，在确保材料及时交付方面进行保证。

2、The artist and the gallery precontracted the terms of the exhibition before finalizing the agreement.
艺术家和画廊在最后确定协议之前预先达成了展览的条款。