酚酞

例句：

1. 1. The color of the solution is a pale pink, which indicates that it contains phenolphthalein.
   溶液的颜色是浅粉色，这表明它含有酚酞。
2. 2. The teacher asked us to observe the reaction of phenolphthalein with acid.
   老师要求我们观察酚酞与酸的反应。
3. 3. The test paper was stained with phenolphthalein, indicating that the sample contained acetone.
   试纸被酚酞染色，表明样本中含有乙酮。