1. [单选题]聚合物薄膜控释系统中，包衣膜hm，药物分子的扩散系数Dm，单位面积体外累积释放量Q，药物在聚合物膜中的溶解度Cp，时间t，若hm较大，Dm极低则（ ）。
A. Q=Cphm/Dmt
B. Q/t=CpDm/hm
C. Q/t=hmDm/Cp
D. Q=CptDm
E. Q/t=hmhmDm
2. [单选题]It took me a long time before I was able to fully appreciate what they __ for me.
A. had done
B. did
C. would do
D. were doing
