It had been raining three days before we arrived, so we might as well _____ at home.

A．stay

B．to stay

C．have stayed

D．to have stayed

被敲响的音叉放入水中，可以观察到水面上的水花向四处溅开，这一实验可以充分的说明，音叉发声是由于音叉________的结果，在音叉发声的同时，迫使周围的________做同样的________。