原发性痛经的主要机理是
A．雌激素升高B．雄激素升高C．孕激素升高D．促性腺激素升高E．前列腺素升高
参考答案：E
When the family moved to Canada, the children _______ very quickly to the new environments.
A．appealed
B．attached
C．adapted
D．admitted
当表格线是浅灰色时，实际打印出来的表格是虚线。
