3 . 根据语境，选择下框中的单词，必要时用其正确的形式替换句中划线部分的单词，使之意思一致。

embarrassed， convince， appetite， invaluable. pose， distinguish， occupy， characteristic， avallable， alternative

1. He is well known for his profound learning in mathematics.
2. The boy is engaged in planning his summer trip.
3. Mary was so awkward. She could only hide her face in shame.
4. I've been trying to persuade him to see a doctor
5. Parents transmit some of their features to their children
6. When he was a child, he had a strong desire for knowledge.
7. These data are not readily obtained if you haven't done some deep research.
8. Some of the measures put in place to deal with the crisis could cause a threat to British interests.
9. Finding himself under fire from all quarters, he had no choice but to abandon his scheme.
10. Experts say it's an precious social practice that results in big benefits.