I． 实验室制备气体，结合以下如图1装置回答问题：

    Far, far away, there is a bad king. All his people 1 him. One hot day, the King goes to swim2 himself in the river.
Suddenly he feels very 3 and can't move his hands and legs. He begins to sink. 4, two farmers are working in the filed nearby and see everything. Of course, the farmers don't know the man in the river is the terrible king. 5 the farmers jump into the river and 6 him.
    The king thanks the farmers and says, “I'm your king. Ask me for7, and I will give it to you.”
“My mother and father are sick in bed,” one farmer says, “Can you give me some 8  to send them to a doctor?” The King agrees.
Then he asks 9 farmer, “How about you? What do you want?” The farmer looks worried and unhappy. “10 let other people know I met you.” he says.

《关于秦汉农业的若干问题》一文中写道：战国初期，粮食产量每亩只有一石半左右（合今1．0517石），而西汉时，据农学家氾胜之讲，在某些地方“中田亩十三石（合今3．76石），薄田亩十石（合今2．89石）”。这说明（    ）