Student or Learner
What's the difference between
-"I'll come to Germany not at a weekend, but on a weekday" and "I won't come to Germany at a weekend, but on a weekday";
- "He is good not only at math, but also at history" and "He isn't good only at math, but also at history"?
Thanks in advance.
In BrE, "at a/the weekend" or "for a/the weekend" are both natural. We don't use "on a/the weekend" (yet!)
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.