Answer:
Since the middle of the 20th century, scientists <u>have found</u> cures for many diseases. However, so far no one <u>has discovered</u>
Explanation:
those are the perfect tenses for (find) and (discover)
Help meeee with my question please
A formal tone would take place in the first box (top left) and the bottom box. An informal tone for example, would be in the top right box. You can find out how to analyze these by reading them aloud. Do they sound formal as if you’re in a meeting with a business? Or do they sound like you’re just sitting in your home and talking normally?
For me it would be option C.
I've chose that as my answer.
