如图1所示，闭合开关，改变R₁阻值，在表中记下几组电流表、电压表的读数．如图2已作出R₂的U﹣I图线．

已知 $\{\begin{array}{c}x=\mathrm{2k}\\ y=-\mathrm{3k}\end{array}$ 是二元一次方程2x-y=14的解，则k的值是____

    Spring is coming．People in different countries like different outdoor activities．Leo，a reporter from Learning English in interviewing（采访）some students．Here is what they have said．
    Mary （13, America）　　
    I want to go out of the city to a beautiful field. It's happy to smell beautiful flowers, touch green grass and take some photos. And I like to have a picnic in the field, It's interesting!
    Jim （14, Canada）　　
    The weather turns warmer and they days become longer in spring. It's a good time to go camping. It would be fun to sleep in a tent. I enjoy the comfortable weather too.
    Tony （13, England）
    In spring, I like going cycling alone. It can not only make me enjoy the beautiful season but also help me became stronger. I can write something about what I see on the way.
    Wang Fang （12, China）
    I'm good at making all kinds of kites. And in spring. I like flying kites with my family or my friends in the park. One of us holds the kite. and another one catches the line. It's exciting to see the kite flying high in the sky.

目前，我国社会总体上是和谐的，但也存在不少影响社会和谐的矛盾和问题：“2009年你最关心经济发展中的哪些问题？”中国政府网显示，看病难排在第一位，还教育收费、收入差距、社会保障等。