听句子，缩写原文。（）

A．I don’t think you have more to say on that topic.

B．I think we’d better talk about that in detail sometime later.

C．I am truly appreciative if you can elaborate on that topic after lunch.

D．I am busy right now, so we might as well discuss it over lunch today.

彩色喷墨等彩色图形印刷设备选用CMY(青、品红、黄)三原色，是( )混色系统。

A．减色

B．加色

C．发电反射

D．比例乘积色