下列直接影响动物种群密度变化的是[ ]
A.出生率、死亡率和迁入、迁出
B.年龄组成和出生率、死亡率
C.性别比例和出生率、死亡率
D.性别比例和年龄组成
答案:A
Your friend _____ doesn't work hard asks you to help him cheat in the exam by looking at your paper.
A. who
B. whom
C. which
D. whether
服装号型标准中,男子、女子共有()个控制部位?
A.10
B.9
C.8
D.7