踏板传动粱的作用是什么？
参考答案：
通过杠杆作用，实现踩下踏板，抬起踏板支棍的作用。
I fell down and broke three of my teeth.I wonder how many times I have to come here and
get my false teeth . [ ]
A. fix
B. fixed
C. fixing
D. to fix
节能的技术途径有哪些内容？
