锅炉安全门是锅炉主蒸汽压力高保护的重要装置。
参考答案:对
* * 损伤后,有排尿困难,导尿管能插入膀胱,应将导尿管留置多久()
A.10~14天
B.1天
C.3~4周
D.5天
E.5~6周
My brother _____ writing the report after breakfast and handed it in at noon.[ ]
A. set off
B. set down
C. set out
D. set about