IoftengotobedlateeveryfridayeveningA.onB./C.inD.at答案上说是选B,为什么不是选A?

Question

I often go to bed late ____ every friday evening A.on B./ C.in D.at 答案上说是选B,为什么不是选A?

Answer 1

因为在every yesterday tomorrow next last this that等这些词所修饰的表示时间的名词前不用任何介词.所以这个选b