地球上昼夜不断交替的原因是 (    )

用相对论的观点判断，下列说法正确的是(  )

把$f\left(x\right)=\cos 2x-\sin 2x+2$的图象沿x轴向左平移m个单位(m>0)，所得图象关于$x=\frac{17}{8}\mathrm{\pi }$对称，则m最小值是(　    )

完形填空
    This is an educational story．A teacher once told each of her students to bring an empty plastic bag and a large bag of 1 to school．If there was someone in their lives that they 2 to forgive，they chose a potato，  3  the name of that person and the date on it, and then put it  4 the plastic bag．Some of their bags were quite heavy．
    They were then told to5 these bags with them everywhere for one week，putting them beside their beds  6 and next to their desks in the classroom．
    As they carried the bags around with them，they 7 what a weight they were carrying，and how hard they needed to pay attention  8 ． Of course，the potatoes were rotten(腐烂的)soon，and smelled  9 ．
    This is the same as the price we pay for keeping our pain and unhappiness with us!So 10others is not only a gift for them，but also a very good gift for ourselves．

若N_A为阿伏伽德罗常数，下列叙述错误的是（    ）