Leave your key with a neighbor _______ you lock yourself out one day.

A.ever since B.even if C.soon after D.in case

Leave a camera on a mountaintop, and chances are, you'll never see it again. But 24-year-old Paul Bellis, a university student from Wales, believed that most people were better than that, and set up a creative experiment to test out his theory.

"I was speaking to a friend who said you can't trust anyone, anywhere these days," Bellis told the Daily Mail. "I didn't want to believe that so I set up this experiment to find out what might happen and prove you can trust people."

Billis decided to do an experiment by hiking up a mountain called Snowdonia, taking a photo, and leaving his camera behind. He also attached a note to the camera, asking other hikers to take photos of themselves and then leave the camera there until the roll of film (胶卷) was empty. He also included his address, in case someone would be nice enough to return the camera to his home after the roll of film was finished.

Four days later, Bellis got a visit from a Snowdonia park manager, who came to return his camera. After Bellis got the film developed, he saw that his fellow hikers and followed his instructions. Thirty people had each taken photos of themselves at the mountain. From viewing the collection, it was clear that all the hikers had enjoyed the experiment.

As for the park manager, Brian, "I found the camera and thought it had been lost until I saw the note," he said. "I was passing his home and just dropped it off. I' m glad that the photos came out very well."

The underlined word "that" in Paragraph 2 refers to __________.

A. the Daily Mail

B. Bellis' theory

C. the idea that Bellis would do the experiment

D. the opinion that we shouldn't trust people

What can we know from the note Bellis attached to his camera?

A. The camera wasn't a missing one.

B. The roll of film had been used up.

C. Bellis was very kind to other hikers.

D. Bellis asked others to take pictures of him.

Brian returned the camera directly because __________.

A. he wanted to be trusted by others

B. Bellis' home was on his way

C. Bellis asked him to do so

D. he wanted to have a look at the photos

The experiment Bellis turned out to be __________.

unsuccessful    B. disappointing    C. encouraging     D. surprising

. Leave your key with a neighbor __________ you lock yourself out one day.

A. ever since   B. even if

C. soon after   D. in case

Leave your key with a neighbor _______ you lock your-self out one day.

A.ever since                                                     B.even if

C.soon after                                                     D.in case

Leave your key with a neighbor ___  you lock yourself out one day.

A． ever since  B． even if    C． soon after      D. in case