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)
1. The boys are full of mischief and always looking for trouble.
2. I waited at the starting line to begin the race.
3. He arrived late because he had an appointment elsewhere.
4. After much discussion, he approved the project.
Hope that helps!
My students are not only intelligent but also...
d- make me laugh.
Answer:
Explanation:
Imagine that you are seven years old. You are participating in an experiment. A
researcher greets you and shows you into a small room. In the room there is a
marshmallow. The marshmallow is for you, but here is the interesting part: The
researcher tells you that he is going to leave you alone in the room for a while. You can
eat the marshmallow right away, or you can wait until he gets back. If you wait until he
gets back, you will get a second marshmallow.
