【They 主句主语】【could only spend谓语动词】【 about fifteen minutes 宾语】【on 谓语动词搭配的介词 】【the summit 介词宾语】【before they had to come down.时间状语从句】
before 【they从句主语 】【had to come down谓语】.
祝你开心如意!
【They 主句主语】【could only spend谓语动词】【 about fifteen minutes 宾语】【on 谓语动词搭配的介词 】【the summit 介词宾语】【before they had to come down.时间状语从句】
before 【they从句主语 】【had to come down谓语】.
祝你开心如意!