小李所住小区附近的某楼盘工地近段时间凌晨三四点仍在施工，发出的轰响声严重影响到小区居是的睡眠。小李欲向政府部门反映此事，你认为应该找（    ）

如图所示，一物体以某一速度冲上表面粗糙的固定斜面，请画出物体在上滑过程中所受的重力G和摩擦力f的示意图．

阅读下面短文，在空白处填入一个适当的词，或填入括号中所给单词的正确形式。    I had my summer all planned out．I was going to enjoy the city． However, my parents had ____ different idea．They said l would be going to my grandparents' farm ____ a whole month．I felt sad．What could ____ (possible)be fun to do in the country?
    It was very hot when we arrived at the farm．So Grandpa took ____ (I)to a creek(小溪)．It felt great to jump into the cool，clear water．I ____ (begin)to think staying in the country might be ____ (interesting)than I had thought．
    The next day Grandma gave me a basket and sent me out ____(pick)strawberries．The berries were so good that a lot of them had disappeared ____ they reached my basket．
    I didn't get to visit a zoo， but l got an up-close look at pigs，cows，and ____ (chicken)．I fed the goats，milked the cows，and collected fresh eggs．
    My summer wasn't what I had expected，____ I loved it! I was sad that I had to leave．Now, I still love living in the city，but I learned that trying new things can be a lot of fun，too!

龚自珍的诗：“九州生气恃风雷，万马齐喑究可哀。”意思是说，当时的思想界陷入沉闷气氛中。你知道出现这种局面的主要原因是什么（   ）

下列实验操作正确的是（   ）