Passage Four
My boyfriend really enjoyed canoeing（划独木舟）,and it took me a while to finally persuade him to take me on a canoe trip. Despite his great skill, he was nervous about my safety and described many terrible situations that could happen. u They could also not happen,M I said. I wanted to prove that I was tough and capable of adventuring.
This would be a romantic adventure. We would row the canoe on the lake under a beautiful blue sky. I was confident it would all go according to plan.
It did not go as planned. Instead, 【it all went downhill】. We hit a headwind （逆风）.The flies were the worst. An unknown animal outside our tent in the night forced us to get up twiceto scareit away.
We walked through knee-deep mud ； we moved around so many fallen trees that we lost the way frequently. We had an unexpected thunderstorm on our second night. We hid in our tent from the bugs（虫子），too tired and bitten to even hold each other. When we were finally back in the car,my skin was hot and angry with bug bites, I had barely slept in 72 hours and I had an injury on my forehead from hitting it on the canoe.
Yet I realized that I wanted to do it all again. Because I swam in a lake so warm it felt like a summer pool. I ate lunch on an island with the most beautiful pine trees. I'd also never before appreciated how thunder can make the ground tremble. I know why my boyfriend loves canoeing so much. It's for the challenge, the space, and the beauty of moving forward with your own two hands in a place of natural wonder. He didn't say " I love you. " He said I was a good partner. I've found something that I really like to do. That's the more important thing.
49.What does the sentence "it all went downhill" in Paragraph 3 mean?