--- Where ____ the recorder? I can’t see it anywhere.

--- I ____ it right here. But now it’s gone.[ ]

A.did you put; have set up    

B. have you put; put

C. had you put; was putting    

D. were you putting; have put

木通主含（）

A．生物碱

B．蒽醌

C．皂苷

D．黄酮

E．木脂素