Are these prepositions correct? Almost. At five o'clock = fine on 14th February = fine (but 'on February 14th' is more common in US English) at midnight = fine on Mother's Day = fine on September : NO. It should be 'in September' in Spring = fine At the holidays = NO. I should be 'in the holidays' or 'during the holidays' At the weekend = fine in British English ('on the weekend' in US English) on the 21st century = NO. It should be 'in the 21st century' This really isn't as complicated as it looks. Just remember this: Use 'at' for times on the clock - at 5 'clock, at midnight, at lunchtime Use 'on' for single days - on Monday, on 14th February, on Mother's Day, on my birthday, and so on. Use 'in' for all longer periods - in September, in Spring, in the holidays, in 2005, in the 1990s, in the twentieth century, and so on. The only odd one is 'weekend', which is 'at the weekend' in British English, but 'on' in American English. Not so difficult, is it?

Your prepositions are perfect British English. Keep in mind that the use of prepositions is slightly different in American English. Keep in mind that people will still understand you even if you get the prepositions wrong. What is far more important is the proper formation of questions – we need to use inversion unless the question word is the subject, which is not the case here. Your question should be "Are these prepositions correct?"

Hi Andrea, I agree with Mary's points but I would add that use of prepositions can vary depending on the English speaking country. What is standard in American English is not necessarily standard in British English. In The U.S. we say "on the weekend" while they say "at the weekend " in England. We say "on a team" and in England they say "in a team" For the most part we use the same prepositions and of course we understand each other. Good work and keep learning. Prepositions are difficult to master so good luck, Dave

At five o'clock - correct on 14th February - correct, or on February 14th also correct at midnight - correct on Mother's Day - correct on September - only use ON if you specify the day/date. Otherwise, IN September in Spring - correct At the holidays - understandable, but DURING the holidays is more common At the weekend - understandable, but ON the weekend is more common on the 21st century - IN or DURING the 21st century Well-done, and best of luck to you!