工作人员 / 确认 / 保险带 / 已经 / 扣紧 / 后 / 才 / 让 / 游客 / 开始 / 攀岩

工作人员确认保险带已经扣紧后，才让游客开始攀岩。

Only after confirming that the safety harnesses were securely fastened did the staff allow the visitors to start rock climbing.