An 18-month-old child is brought to the emergency department with suspected croup. The child appears frightened and cries as the nurse approaches him. The nurse needs to assess the child's breath sounds. The best way to approach the child is to

A．expose the child's chest quickly and auscultate breath sounds as quickly and efficiently as possible.

B．ask the mother to wait briefly outside until the assessment is over.

C．tell the child the nurse is going to listen to his chest with the stethoscope.

D．allow the child to handle the stethoscope before listening to his lungs.

为改善操纵系统特性，在助力操纵系统中除助力器外，还必须加装的部件有：（）

A、载荷感觉器和调整片效应机构

B、载荷感觉器和张力补偿器

C、张力补偿器和调整片

D、舵面锁和载荷感觉器