四、从短文后的选项中选出可以填入空白处的最佳选项
Pigeons are amazing birds that have 1. (help) humans for centuries. They 2. (have) a special place in people's hearts because of their loyalty and ability to find their way home. Unlike many other birds, pigeons have a strong sense of direction, so they can 3. (find) their way back even from faraway places.
In the past, when there 4. (be) no modern communication tools, pigeons were very important. People used them 5. (send) messages between different places. These 6. (brave) pigeons flew through bad weather and dangerous areas, and some even 7. (save) many lives by delivering important information in time.
Today, pigeons still 8. (living) around us. They are 9. (friend) to people and often live in parks or squares. Many people like to feed them and watch them fly. It's our responsibility 10. (protect) these lovely birds and all animals, because they make our world more beautiful and meaningful.

1. helped
2. have
3. find
4. were
5. to send
6. brave
7. saved
8. live
9. friendly
10. to protect