不属于高分子化合物的特点是()。
A.比强度高
B.弹性模量高
C.耐热性差
D.耐腐蚀性好
参考答案:B
_____ it take you to walk from your home to your office? [ ]
A. How long is
B. How far is
C. How long does
D. How far does
从侧方观察脊柱,有哪几个生理弯曲?分别凸向何方?有何生理意义?