___ waiting for the bus.

A．They both are

B．They are both

C．They both will be

D．Both they are

颈部手术操作，患者突然低血压和心率减慢，最可能是()

A．刺激了喉返神经

B．刺激了喉上神经

C．刺激了颈上神经

D．颈动脉窦神经反射

E．窒息