某化学兴趣小组对教材中“测定空气里氧气含量”的实验（见图I）进行了大胆改进（见图Ⅱ），选用容积为30mL的18×180mm的试管作反应容器进行实验，收到了良好的效果．请你对比分析下面图I、图Ⅱ的实验，回答下列有关问题：

3名学生排成一排，其中甲、乙两人相邻的概率是                     (     )

如图所示，通电直导线旁放有一闭合线圈abcd，当直电线中的电流I增大或减小时（　　）

根据短文内容, 回答下列问题。
    I am Helen. I study in the No.1 Middle School now. There are forty-five students in my class. All of the students like to travel(旅游). Eight students like to travel by plane, because they think it is fast. It only takes about two hours to travel by plane from Beijing to Shanghai. But some students think taking a plane is too expensive. Twenty-two students usually travel by train. The trains are very fast, but they are cheaper (更便宜). And they can see interesting things through the windows. Fifteen students love to travel by car. Their parents drive them to some beautiful places. They can have a good time with the family. Do you know how I like to travel? I'm one of the twenty-two students.

We must cross the road now. (改为否定句)

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