增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

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（从第11处起）不计分。

    Taking parts in recreation activities help us keep fit. There are different kinds of activity in our daily life, for example, listening to music, watching TV, playing chess, or going to cinema. But I think we'd better to have more outdoor activities. As students, we usually sit too longer in the classroom, and as a result our eyes and brains getting tired. But it is a good idea to play ball games, go swimming, do some runnings, or even go for a picnic. Our brains also need changes to make itself smart and active. In a word, exercise is good for health.

①物种多样性    ②遗传多样性    ③生物多样性    ④生态系统多样性