27．Thinking of his daughter, who was killed in an accident, _______________.

A．his heart sank

B．tears came down his face

C．he was in deep sorrow

D．we found his eyes full of tears

微处理器对I/O口的编址方式有()。
A) 将I/O口地址和主存储器地址统一编址
B) 将I/O口地址和存储器地址分别独立编制
C) 以上都是
D) 以上都不是