如图，两根平行光滑金属导轨固定在同一水平面内，其左端接有定值电阻R．Ox轴平行于金属导轨，在0≤x≤4m的空间区域内存在着垂直导轨平面向下的磁场，磁感应强度B随坐标x（以m为单位）的分布规律为B=0.8﹣0.2x（T）．金属棒ab在外力作用下从x=0处沿导轨运动，金属棒始终与导轨垂直并接触良好，不计导轨和金属棒的电阻．设在金属棒从x₁=1m经x₂=2m到x₃=3m的过程中，R的电功率保持不变，则金属棒（   ）

Complete the sentences with the given words in their proper forms.(用括号中所给单词的适当形式完成下列句子。每空格限填一词)

Some people like reading on Wechat, but ____  don't. (other)

Cut the strawberries into pieces and put ____  into the yogurt. (they)

The day was ____ , but the sun was trying to come through. (cloud)

I'm thankful to the teacher for her ____ on my interview. (suggest)

It's our responsibility to make the sky ____ than before. (clear)

Education is one of the most powerful ways to ____ one's mind. (rich)

I think it's ____ to judge a person before you really know him. (fair)

____ , the famous temple was not damaged in the earthquake. (luck)

如图表示人体内某种酶促反应的反应速率受温度和pH的影响情况，下列解释不正确的是（　　）

等腰三角形的两边长分别是4和9，则这个等腰三角形的周长是（   ）