_____.

Key：

I. 1. permanent 2. donated 3. souvenir

4. phenomenon 5. overhead 6. barrier

II. 1. exploration 2. ripen(ed) 3. poisonous

4. settlers 5. permitting

III. 1. made headlines 2. in case 3. kicked off

4. dropping off 5. dropped in on

6. end with 7. defend; against

8. a stepping stone

9. in all four corners of the globe