Blood vessels in the head tighten to stop the loss of body heat and then relax to let blood flow rise; that sudden rush of blood is what causes the headache.
头部的血管收紧以阻止身体热量的流失，然后放松让血液流动起来，血液的突然涌入是引起头痛的原因。
2
The response is to increase blood flow to the area and increase body heat.
应对方法是增加流向该区域的血流量并升高体温。
3
If there's no heatflow between the b and c, then I can say all right, a and c were the same temperature.