晚期囊胚透明带消失后，相当于受精后第几日开始着床：
A．2～3日
B．4～5日
C．6～7日
D．8～9日
E．10～11日
参考答案：C
The lamb _________already. It_ __________for 2 days.
A．has died , has been dead
B．died, has been dead
C．has been dead, died
D．died , has died
Corporations and labor unions have______great benefits upon their employees and members as well as upon the general publiC．
A．conferred
B．granted
C．flung
D．submitted
