Answer: libraries aren’t tools, but they are very useful for research. They are quiet, and have books with all sorts of facts
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)
Answer:. To establish credibility with the interviewee
Explanation:
