粮店有大米20袋，面粉50袋，共重2250千克，已知1袋大米的重量和2袋面粉的重量相等，那么一袋大米重____ 千克。

 Tim was reading a book at office. Someone knocked on the door. He opened the door.____  .
"My name is Rebecca," said the lady. "You've got to help me!"
"Take it easy." ____ "What happened?"
"My grandma died last month. She left all her money, about $1,000,000 to me. She told me she had saved the money in a bank.____ . "
"But yesterday when I went to the bank, I only got an envelope with nothing in it. he money is gone!"
Rebecca took the envelope out of her handbag and gave it to Tim.
Tim looked at it carefully under the light. It was just an envelope with two old stamps on it. ____ 
“Don't worry, Rebecca," he said. "Your money is still here.”

读下面的句子，给划线的字注音。

①小松鼠长____着一条长长____的尾巴。

②听音乐____是一件快乐____的事。

③望着____窗外的大雨，奶奶心里很着____急。

反应：2A(g)＋B(g)2C(g)，当平衡向正方向移动时，下列说法一定正确的是