文青，这课我还没听。所以语调说不出来什么。应该注意的是nasal consonants。
ng我目前的水平还听不出来毛病。
N，M 应该有鼻腔震动的感觉，你拿拇指，食指和中指触摸鼻腔，发N，M时，感觉到震动的声音吗？
Lesson20:Hiking
286. My feet are sore from hiking.
287. We can rest at the top of this hill.
288. I like hiking in real wilderness.
289. Hiking is not yet popular in China.
290. The trail splits into two trails.
291. The rest of the way is downhill. 尤其感到N不到位。
292. Be careful of the slippery rocks.
293. Is your pack comfortable? l也发得不到位，像小麦熊给bingli说的，舌根下压，舌尖顶上颌。r没发。
294. I hate people who litter in the forest.
295. Too much noise scares the animals away.
296. How much farther do we have to go?
297. It seems like we’re been walking forever.
298. Sorry, I didn’t realize you were getting so tired. r怎么没发到位呢？？？
299. This view is absolutely breathtaking. Don’t you agree?
300. It’s a feeling of satisfaction that we are getting so much exercise and clean air, and see so many magnificent sights.
