“正片”造句

彩色正片的彩色再现过程,基本上和彩色负片相同.
Color positive emulsions basically perform in the same way that color negati ves do.

正片什么时候开始?
What time does the main feature start?

正片九点开始放映到十点半结束.
The feature started at 9 o'clock and ended at ten thirty.