已知样本容量是40，在样本的频数分布直方图中各小矩形的高之比依次为3:2:4:1，则第二小组的频数为____，第四小组的频率为____．

小组同学利用电压为6V的电源、阻值为15Ω的定值电阻R₀，量程为“0～0.6A” 和 “0～3A”的电流表及二氧化锡电阻Rx制作成甲烷气体浓度检测仪，其电路图如图所示。当甲烷气体浓度增大时，电流表的示数将____ (变大／变小／不变)。为使读数更为准确，电流表的量程应选____ 

    Hello! My name is Lily. I'm ten years old. I'm in Class Three, Grade Three. Look! This is my new schoolbag. It's red, I like red very much. I have English and music today. I like English very much. I like hamburgers and hot dogs, too. I have a dog, its name is Benben. It's small and white. It's very lovely. I love it.

根据短文内容，判断正误。

指出下列各句中，“为”字的意义和用法不同的一项是(      )。