在下列遗传系谱中，一定是常染色体上隐性基因决定的遗传病的遗传系谱是(图中阴影者表示患者)[ ]
A．
B．
C．
D．
答案：C
PC键盘布置了83个键，内部由一块()MPU控制，它是典型的8位单片机。
A．8255
B．8049
C．8259
D．8237
Organizations perform work to achieve a set of objectives. Generally, work can be categorized as either projects or operations, although the two sometimes are（）
A.confused
B.same
C.overlap
D.dissever
