Some of my friends are interested in science,but none of them can tell_____.

A．when UFOs will appear next time.

B．why do horses know the way.

C．where was this kind of plant found.

D．how do elephants communicate.

宜饭后服用的药物是（）

A.驱虫药

B.安神药

C.补益药

D.对胃肠有刺激的药

E.截疟药