—What about watching the movie Big Fish tomorrow?
—Oh, I it already.
A:watch
B:have watched
C:will watch
D:am watching
人们在买陶瓷用品时,常常用手敲一敲,再用耳朵听一听,便可知道陶瓷用品是否破损,这主要是根据声音的 ____ 特征来辨别。