In 2005,3.38 million students graduated from colleges and universities, ______20% increase from2004, some of whom remain out of______work.

A．(不填); (不填)

B．a; (不填)

C．a; the

D．the; (不填)

关于绒毛膜促性腺激素，下列哪项正确：

A．由绒毛细胞滋养细胞产生
B．分子量约为5万
C．有与黄体生成激素相似的生物活性
D．为糖蛋白激素，糖分子量占70%
E．至妊娠4～16周达高峰，持续1～2周后下降