I know that time expressions can be placed at the beginning or at the end of the sentence. For example:
At eight, I get up to go to school.
I get up to go to school at eight.
After lunch, I go to bed.
I go to bed after lunch.
That seems to be correct. But for some reason this sentence sounds strange to me.
In the morning, I get up at eight o'clock.
However, this another one sounds good to me.
I get up at eight o'clock in the morning.
I mean, is "in the morning, I get up at eight o'clock" correct?