sealed biddings

例句：

1. 1. The company is offering sealed biddings for the new project.
   该公司正在为新项目提供密封投标。
2. 2.In sealed biddings, bidders submit their proposals to the auctioneer.
   在密封竞标中，投标人将他们的提案提交给拍卖师。
3. 3. The sealed biddings process ensures that only qualified bidders can participate.
   密封竞标过程确保只有合格的投标人可以参与。