Many scholars share the belief that interest is as _____ to learning as the ability to understand, even more so to some degree.

—Do you have any idea why Mark is leaving?—No. In fact，everyone is _________about it. 

The necklace the woman bought is          , because it is made of glass.

—Will you be____this afternoon, Jack? —It depends．I’m afraid I’ll be called by my boss．

 It is reported that the United States consumes ______ energy as the whole of Africa.