动听的音乐在计算机中是以()的形式保存。
A、声波
B、声响
C、频率
D、文件
参考答案:D
After school was over the boys ________ their books and went home.
A.put in
B.put aside
C.put away
D.put up
浸出物的含量测定主要是指
A.脂溶性浸出物测定
B.水溶性浸出物测定
C.醚溶性浸出物测定
D.酸溶性浸出物测定
E.醇溶性浸出物测定