1. I haven’t seen my brother for two months.
=> I last saw my brother two months ago.

2. Wear a hat or you’ll get sunburnt.
=> If you don't wear a hat, you’ll get sunburnt.

1. I haven’t seen my brother for two months.
=> I last saw my brother two months ago.

2. Wear a hat or you’ll get sunburnt.
=> If you don't wear a hat, you’ll get sunburnt.