阅读短文，从方框中选择适当的单词填空。

Some people in Britain and America like to invite friends to dinner at home. But this is more common in America (1)______________ in Britain. Don’t worry if your English friends don’t invite you home. It doesn’t mean that (2)______________ don’t like you.

When you are invited to an evening dinner, ask your friends what (3)______________ you should arrive. It is a good idea to take a small present when you arrive, and it is (4)______________ to say how much you like the house, the room, or the pictures in the room. But don’t ask how much these things cost. In this way, (5)______________ you and your friends will have a pleasant get-together.

导致心肌收缩加强的肾上腺能受体为

A．N₁受体
B．N₂受体
C．α受体
D．β₁受体