石油沥青老化后，其软化点较原沥青将______。
A．保持不变 B．升高 C．降低 D．先升高后降低
参考答案：B
I have never seen to lose any weight, _____hard I try. [ ]
A. even though
B. no matter how
C. as if
D. ever since
如下图所示的事例中，通过热传递的方式改变物体内能的是
