Once there was a king called David. He lived in a golden place with his 1. He was rich, but he still loves 2 very much.

    One day, a god called Gory got lost and woke up in the garden of David's place. The king 3 him for some days. Gory was very grateful (感激的) and 4 to give David anything he wanted. David was happy and said, "I would like everything I touch to turn into gold."

    At first David was very 5. He touched a table and it became gold. But as he reached out for an apple, it turned into gold and he couldn't 6 it. David became scared. At that moment, his daughter entered the room. David rushed over to hug her. Suddenly, he realized that his daughter was a 7, golden statue (雕像). David cried 8. Then he turned to Gory. Gory told him to go down to the river and wash his 9. David did as what Gory told. Then he returned to the 10. He found everything changed back when he touched the gold.

    From then on, David didn't care for gold any longer.

如图所示，A、B、C三个物体放在旋转平台上，与转台相对静止，动摩擦因数均为μ已知A的质量为2m，B、C的质量均为m，A、B离轴距离均为R，C距离轴为2R，则以下说法正确的是（   ）

『新年前夕，******发表了2017年新年贺词，一句金句“大家撸起袖子加油干”迅速走红网络，成为人们热议的新词。某校九年级1班围绕“大家撸起袖子加油干”主题，从“加油干的目标”、“加油干的品质”“加油干的要求”进行了研究性学习。请你运用所学知识帮助他们解决探究中的问题。』

【加油干的目标】“目标组”的同学围绕2017年***新年贺词，进行了探究。

巴西以生产和出口热带经济作物闻名，____ 、____ 、柑橘等产量均居世界首位．