已知：∠α．请你用直尺和圆规画一个∠BAC，使∠BAC=∠α．

（要求：不写作法，但要保留作图痕迹，且写出结论）

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.

如图所示曲线表示某人在休息状态中进行一次呼吸时，肺内空气压力的变化．当时大气压力为760mmHg．据图分析并回答下列问题：