II.短文改错（共10小题；每小题1分，满分10）
下面短文中有10处语法错误。请在有错误的地方增加、删除或修改某个单词。
增加：在缺词处加一个漏字符号（∧）,并在其下面写上该加的词。
删除：把多余的词用斜线（\）划掉。
修改：在错的词下划一横线，并在该词下面写上修改后的词。
注意：1.每处错误及其修改均仅限一词；
2.只允许修改10处，多者（从11处起）不计分。
A boy who was cleaning the shoes in the street said to a young man passed by , “Let me clean your boots . It’ll spend you only a penny .” But the young man refused. Then the boy told him that he will clean his boots for nothing .The young man agreed, and soon a boot shining brightly .Then he put the other boot on the box , and the boy refused to clean it unless he was paid two pence for his work . The young man refused to pay for anything and went away . But the well-cleaning boot made the dirty ones so bad that he couldn't walk on . He returned back and gave the boy two pence .
A boy who was cleaning the shoes in the street said to a young man passed by , “Let me clean
去掉 passing
your boots . It’ll spend you only a penny .” But the young man refused. Then the boy told him that
cost
he will clean his boots for nothing .The young man agreed, and soon a boot shining brightly .Then
would 前加was或shone
he put the other boot on the box , and the boy refused to clean it unless he was paid two pence for
but
his work . The young man refused to pay for anything and went away . But the well-cleaning boot
去掉 well-cleaned
made the dirty ones so bad that he couldn't walk on . He returned back and gave the boy two
one back去掉或returned改为turned
pence .
2CA3（g）达到平衡时，不断改变反应条件(不改变A2、C2和CA3的量)，下图表示反应速率与反应过程的关系，其中表示平衡混合物中CA3的含量最高的一段时间是____________________。 