Common Mistakes : At

 preposition

.BAD: I always have a good breakfast at the morning

.GOOD: I always have a good breakfast in the morning

.BAD: At afternoon I visited the Fitzwilliam Museum

.GOOD: In the afternoon I visited the Fitzwilliam Museum

.BAD: In Germany we have a lot of snow at wintertime

.GOOD: In Germany we have a lot of snow in wintertime

.BAD: I was married at 1989 and have two children, a boy and a girl

.GOOD: I was married in 1989 and have two children, a boy and a girl

.BAD: I bought the tape just a week ago, at 4th December

.GOOD: I bought the tape just a week ago, on 4th December

.BAD: We were all very tired at the last day of our journey

.GOOD: We were all very tired on the last day of our journey