It's seven o'clock in the evening.It'timedinner.A.in B.for

題目：

It's seven o'clock in the evening.It'time()dinner.A.in B.for C.at
請說明爲什麼

解答：

It's seven o'clock in the evening.It's time (B.for) dinner.
現在是晚上七點.到吃晚餐的時間了.
It's time for sth,到了做某事的時間.這裡要用介詞for表示「對於……」.
再問： 爲什麼不能用to呢？^_^
再答： 用to的時候是用的動詞不定式，而不是動詞。這句話應該這麼表達： It's time (to have) dinner. 也就是說to要和動詞原形一起用。