题目内容：

Heroes come in all shapes and sizes. Some heroes, like Lucca, are not even humans. Lucca is a 12-year-old US military (军队的) dog. On April 5, she received an award (奖) for her brave military service.

Lucca and her owner, Christopher Willingham, traveled to London, England, to receive the PDSA Dickin Medal. It is the highest award for service animals.Lucca is the first US military dog to receive the medal. “Lucca is very clever and had an amazing drive (干劲) for work as a search dog,” Willingham said. “I am lucky to have served with her.”

During her six years of active military service, Lucca completed more than 400 jobs. She was trained to find explosive devices (易爆装置). Lucca's skills protected the lives of thousands of people.

One day in 2012, she was searching for explosive devices with her trainer, Juan Rodriguez, as usual. Unluckily, she lost her left leg after walking on a device. She was quickly sent to hospital. Thanks to the doctors' help, Lucca was saved. During that time, Rodriguez remained at Lucca's side. “She had saved my life so many times — I had to make sure that I was there when she needed me,” Rodriguez said. “Within 10 days, she was walking again. Her fighting spirit was plain to see.”

Lucca doesn't work now and lives in California with Willingham and his family. “I'll do my best to keep her happy in her last years,” Willingham said.

Lucca is the 68th animal to receive the PDSA Dickin Medal since it was created in 1943. The award has been given to 31 dogs (including Lucca), 32 World War II messenger pigeons (信鸽), four horses and one cat.

根据材料内容选择最佳答案。

1.Lucca went to London with her owner to _____.

A. do a job

B. have a holiday

C. get an award

D. receive training

2.Paragraph 3 mainly talks about Lucca's _____.

A. popularity

B. achievements

C. everyday life

D. rapid progress

3.What does the underlined word “plain” in Paragraph 4 mean?

A. Sad.

B. Hard.

C. Fun.

D. Clear.

4.What can we know about the PDSA Dickin Medal?

A. It was created in America.

B. It has a history of 100 years.

C. It was named after a messenger pigeon.

D. It has been given to four kinds of animals.

5.The writer wrote this passage mainly to introduce _____.

A. a brave dog

B. a famous award

C. some animal heroes

D. some dangerous jobs