Mary went to Canada on vacation. After a week, she came back to New York. She told lots of interesting things to her best friend, Jack. Jack was very interested in Canada and decided to have a visit there. The next summer vacation, Mary and Jack had a plan to go to Canada together. But her mother was badly ill so she went to the airport to see her friend off. When they got to the airport, Mary had to got to the washroom. When she came back, she couldn't find Jack because there were so many people at the airport. She looked for him everywhere, but it was hard to find Jack among the people. Suddenly Mary saw Jack and she felt very happy, so she shouted,"Hi, Jack. Here, here." At the same time, Jack waved his arms,"I'm here." In 3 minutes, so many policemen came to the front of Jack and caught him, "Please come with me to the police office." After the policemen found out the reason, they let them free. Why? Because the word "hijack" in the English has different meanings. Why was it hard for Mary to find Jack at the airport?   _   .
Because Jack was in the plane. Because there were too many people. Because he was in the washroom. Because the policemen took him away from the airport.