单项选择题
It is helpful if you stop and think what are the streng...
单项选择题It is helpful if you stop and think what are the strengths and weaknesses of your research and your method.（ ） A. 对 B. 错
（ ）一般不单独使用，常与轨道遮罩、差值遮罩等其他键控方式相结合，用来调整透明和不透明部分的交界线，扩大或缩小...
单项选择题（ ）一般不单独使用，常与轨道遮罩、差值遮罩等其他键控方式相结合，用来调整透明和不透明部分的交界线，扩大或缩小透明区域的范围，移除其他键控效果没有抠除干净的背景部分，所以该方式一般在轨道遮罩或差值遮罩之后使用。 A. Alpha调整 B. 图像遮罩键 C. 移除遮罩 D. 差值遮罩
Why did printing become possible? A、Because Chinese ...
单项选择题Why did printing become possible? A、Because Chinese people were very hard-working. B、Because Chinese people learned that from the westerners. C、Because of the invention and improvement of papermaking. D、Because Chinese government sent many people to study that.
