(74) systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and (75) on the disk, and controlling peripheral devices such as disk drives and printers.

A．contents

B．diectories

C．directions

D．direct

男性，32岁，电工，操作时不慎触电，心跳呼吸骤停来院急诊，迅速心肺复苏

心脏复苏按压的部位是（）

A．胸骨柄

B．胸骨上段

C．胸骨中段

D．胸骨下段

E．胸骨剑突