变性珠蛋白小体的形成是
A．胞浆内存在RNA
B．胞浆内嗜碱性物质因中毒变性
C．不稳定Hb
D．核的碎裂，残存物
E．红细胞膜的异常
参考答案：C
There is no doubt our educational system leaves something to be desired．
A．what
B．whether
C．if
D．that
– Is your brother going to Jack’s birthday party tonight?
– I am not sure. He _____ go to the concert with his girlfriend instead.
A．ought to
B．has to
C．might
D．must
