At the opening________of the school, our headmaster gave a short speech.

A．ceremony

B．form

C．matter

D．event

半夏内服的功效为（）。

A.温化寒痰、温肺化饮、降逆止呕

B.燥湿化痰、降逆止呕、消痞散结

C.燥湿化痰、祛风解痉、降逆止呕

D.温化寒痰、燥湿化痰、消肿散结