加药调节相界面的物理化学性质，促使气泡与矿粒（）附着，达到彼此分离的目的。
参考答案：选择性
To learn the piece of music quickly, you'd better hear it ___ as many times as possible.
A．play
B．playing
C．played
D．to play
经济发展的推动戏剧演出的社会化与商业化。
