—We all had a lot of fun at the barbecue yesterday. Pity you weren't there.

—I really should have gone with you but I________on some remaining problems.

A．worked

B．was working

C．would work

D．would have worked

藿香正气散中具有表里同治、升清降浊作用的药物是（）

A.紫苏

B.藿香

C.白芷

D.半夏

E.桔梗