The robot didn't know when to cook breakfast.The robot didn't know when____ ____ ____breakfast.

it should cook
when to cook = when it should cook 什么时候应该做饭填it would cook 对吗？（这是老师说的答案，would是will的过去式）也说得过去should意思是应该，应当，would 意思是将要所以　should更适合些，这个机器人不知道何地去做早饭。~~~~~~~~~~～～~~~~祝你进步，如对你有帮助，请及时采纳~~~~~~~~~~~~~~~~