此题要求改正所给短文中的错误。对标有题号的每一行作出判断：如无错误在该行右边横线上画一个勾(√)；如有错误(每一行只有一个错误)，则按下列情况改正。
该行多一个词；把多余的词用斜线(\)划掉，在该行右边横线上写出该词，并也用斜线(\)划掉。
该行缺一个词；在缺词处加一个漏字符号(∧)，在该行右边横线上写出该加的词。
该行错一个词；在错的词下画一横线，在该行右边横线上写出改正后的词。
注意：原行没有错的不要改。
A group of scientists
were planning to go
to countryside to do a
scientific research in order to
86．____
find out that whether
the environment of the country
87．____
had polluted. On
arrival , they started to check the 88．____
air and water. To our
surprise, they found
89．____
how terribly the
situation was. They could see
90．____
the serious pollution.
Look into the cause,
91．____
they persuade the
government to pass the law
92．____
to protect environment
and kept the balance of
93．____
nature. Now everything
has changed. Birds are
94．____
singing while tree and
grass are waving.
95．____