We are invited to a party _________in our club next Friday.

A．being held

B．held

C．to be held

D．holding

颈动脉体和主动脉体化学感受器可感受的刺激是（）

A、白蛋白含量变化

B、氢离子浓度变化

C、钠离子浓度变化

D、钙离子浓度变化

E、钾离子浓度变化