一卵生的双胞胎胖瘦相差很大，原因是[ ]
A．显性基因发生了作用
B．隐性基因发生了作用
C．染色体数目发生了改变
D．生活环境和条件有所不同
答案：D
I like comedies _______ I don't like documentaries at all; they're more than boring. [ ]
A. and
B. but
C. or
D. for
能反映HDL水平的载脂蛋白是
A．ApoAⅠB．ApoBC．ApoCⅢD．ApoAⅡE．ApoCⅠ
