—Where are you ________?

—I’m going to the airport to ________ my friend.

A．heading on; pick up

B．going for; pick down

C．heading for; pick up

D．heading away; pick down

亲水性生物碱不包括( )

A．季铵型生物碱

B．生物碱N-氧化物

C．酰胺类生物碱

D．小分子生物碱

E．酯类生物碱