一、该吃午餐了英语，改为同义句？
回答：
汉语句子“该吃午餐了。”翻译成英语时，它的表达方法有好几种呢！
我们可以用It is time to do sth.或者是：It's time for sth., 也可以说“ It's time for sb. to do sth.” 甚至是可以这样说：It's time that sb. did sth./ It's ( high) time that sb. ( should) do sth.
因此，这个句子的同义句是这样的：
1. It's time to have/ eat lunch.
2. It's( high ) time for lunch.
3. It's time for us to have lunch.
4. It's time that we had lunch.
5. It's ( high)time that we should have lunch.
二、its time for lunch的同义句？
英语中It's time for +名词.=It's time to + 动词。意思是"该做某事了。/ 到了该做某事的时候了。"It's time for lunch.意思是:该吃午饭了。它的同义句是It's time to have lunch. 再举个例子，It's time for school. = It's time to go to school.这个句子的意思是:该上学了。
三、timeforcake还是timeforthecake？
time for cake.该吃蛋糕了，it's time for lunch.该吃午饭了。
it's time for rest.该休息了。
it's time to play badmin.该打羽毛球了。
it's time for bed.该睡觉了。
it's time to go home.该回家了。
it's time to go to work.该上班了。
it's time to go to school.该上学去了。
good.