back-and-forth

After weeks of back-and-forth, both parties finally agreed on the contract terms.经过数周的反复沟通，双方终于就合同条款达成了一致。

The back-and-forth between the design and engineering teams delayed the final product by two weeks.设计团队和工程团队之间的来回沟通使最终产品的交付延迟了两周。