AAC-LD（）kHz采样高保真CD音质支持双声道
A.7
B.16
C.48
D.64
参考答案：C
用托盘天平称量干燥的固体药品时，在两个托盘上各放一张相同质量的纸片，其理由是______．
Amy finishes _____ her homework before 9 p.m every day. [ ]
A. to do
B. doing
C. does
