绝经后女性骨质疏松是由于雌激素不足导致（）
A.骨质生成停止
B.血钙降低
C.骨质吸收增加
D.甲状旁腺功能亢进
E.血钙升高
参考答案：C
Everyone hopes that we can do something to make things better, so we can't help ______ under the stress.
A．but working
B．but to work
C．work
D．but work
