最近苦读户外穿衣理论有些疑问，问题一，各位三层穿衣时穿不穿T恤，还有不穿内裤是不是增加排汗效果？
另见国外一篇文章如下：
Layer #2: Insulating
This layer can actually be a couple layers. It's job is to keep enough body warmth in to keep you comfortably warm while still allowing perspiration to escape. The best way to do that is to have dead air space trapped in pockets. Synthetic fabric such as fleece is usually a good choice.
Moisture is deadly when the temperature drops or when you slow down your pace - you want moisture to get out but not in. Goose down is also a good insulating layer, but is bulky and probably overkill for most hiking outings.
For pants, a pair of nylon zip-off pants is a great layer on top of your polypropylene underpants.
Clothes that are easy to slip on and off are optimal since these insulating layers will be changed as you heat up and cool down
此段话是关于第二层的介绍，这句For pants, a pair of nylon zip-off pants is a great layer on top of your polypropylene underpants.这句话的意思大概是尼龙的二截裤子穿在化纤的底裤外不错，各位有没有下面不穿抓绒，穿
速干裤，外面穿
冲锋裤的经验？感觉如何？
