非谓语动词和过去完成时并不冲突的,它们完全是两个概念,第三句话也可以改成非谓语动词的表述的
1 After having speng whole mornings on the river ,I always go hmoe with an empty bag
= After I spent whole mornings on the river,I always go home with an empty bag
2 Before leaving the room ,he turned off the radio.
= Before I left the room,he turned off the radio.
3After I had lunch at a village pub,I looked for my bag
= After having lunch at a village pub,I looked for my bag.