题目

At night,you are just lying there, but the body is busy.9:00 pm Get ComfortableIt usually takes about 15 or 20 minutes to fall asleep, with the most comfortable position. Some people sleep on their backs and some on their stomachs. Most people curl up in a fetal position like a baby in the womb(子宫). Other people like strange positions like sleeping on elbows(肘部) and knees.9:20 pm I am Falling AsleepYou're about to sleep when suddenly you feel like falling. You even dream you are falling off a cliff. Your body jerks(抽搐). What's happening? Well, you are falling-asleep. Your body rela下列关于温度、内能、热量和做功的说法中正确的是（ ）A．物体吸热，温度一定升高B．物体内能增大，一定是外界对物体做功C．某一铁块，温度降低，内能减小D．物体放热，温度一定下降