at a time, at all times
One of my colleagues sneezes at all times (really haha). (or at all time?)
Please ask me a question at a time.
Are both of them correct?
Is 'at all times' interchangeable with all the time and always?
If any one of you can give me some examples with an explanation, I would be very glad!
Thanks a lot for your help in advance. Have a nice day!