电影特技中常见的“抠蓝”效果多数情况下是利用视频Keying效果中（）效果来实现的。
参考答案：颜色透明类键
Mr. Green stood up in defence of the 16-year-old boy, saying that he was not the one _____.[ ]
A. blamed
B. blaming
C. to blame
D. to be blamed
水果和蔬菜常用的贮藏方式有：气调贮藏、机械冷藏、（）、假植贮藏和堆藏。
