为成人实施胸外心脏按压时，应使胸骨下陷
A．1～2cm
B．5～6cm
C．4～5cm
D．3～4cm
E．2～3cm
参考答案：D
Many strange new means of transport have been developed in our century, the strangest of _____ being perhaps the hovercraft(气垫船).
A．which
B．them
C．that
D．it
民用建筑采用低温热水地板辐射采暖，其供水温度不应超过（）℃。
A．60
B．85
C．95
D．130
