促进精子的发生和发育的是
A．人绒毛膜促性腺激素B．人胎盘生乳素C．雌激素D．孕激素E．前列腺素
参考答案：B
"Two Butterflies" was one of _____ songs of 2005.[ ]
A. popular
B. more popular
C. popularest
D. the most popular
54×46的值是( )。
A．2480
B．2484
C．2584
D．2494
