Some of the books appear to be _______ ones that you have read, but after taking _______ second look, you will find that they are different.

A．/; a

B．the; the

C．the; /

D．the; a

某大学派出5名志愿者到西部4所中学支教，若每所中学至少有一名志愿者．则不同的分配方案共有：

A．240种
B．144种
C。120种
D．60种