从一批电视机中随机抽出10台进行检验，其中有1台次品，则关于这批电视机，下列说法正确的是(   )

At the age of six, my son _____ ask me a lot of strange questions, and some of them were too hard to answer．

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!

在研究“平面镜成像特点”实验中，小明用玻璃板、两支完全相同的蜡烛、刻度尺、白纸等器材进行实验，如图所示：

如图所示,物体a､b和c叠放在水平桌面上,水平力F_b="5" N,F_c="10" N分别作用于物体b、c上,a、b和c仍保持静止.以F_f1､F_f2､F_f3分别表示a与b、b与c、c与桌面间的静摩擦力的大小,则(    )