B.波的传播速度为b/a
C.波长为π/b
D.波的周期为2π/a
答案:D
Helen was much kinder to her youngest son than to the others, _____, of course, made the others envy him. [ ]
A. who
B. that
C. what
D. which
能被β-葡萄糖苷酶分段水解的是
A.胡萝卜苷B.杨苷C.芦荟苷D.苦杏仁苷E.红景天苷