受交感神经支配，导致心率加快的肾上腺素能受体是
A．α受体B．β1受体C．β2受体D．M受体E．N受体
参考答案：B
This is Ted’s photo. We miss him a lot. He ______ trying to save a child in the earthquake.
A．killed
B．is killed
C．was killed
D．was killing
