商务信函的落款可以是个人也可以是单位。
参考答案：对
They arrived at a farmhouse, in front of sat a small boy.[ ]
A. whom
B. who
C. which
D. that
计算机内存的容量大小受到 (11) 位数的限制。若该总线为20位，则可以寻址的内存空间为 (12) B。
A．10K B．20K C．1M D．20M
