smooth sailing ---------- 一帆风顺（成语）

英文释义
(IDIOM) Describing a situation without obstacles.

例句
Although at the start the complicated project was quite difficult for our business team, after a couple months passed it was smooth sailing, and we finished the project on time.
尽管一开始，我们的业务团队觉得这个复杂项目相当困难，但是几个月过后，事情变得一帆风顺，我们按时完成了项目。