机箱的电源按钮带有指示灯。

The power button on the case has an ___indicator.

电池电量指示灯变红时，就该充电了。

When the battery ___indicator turns red, it's time to recharge.

消费者信心指数是经济健康的重要指标。

The consumer confidence index is a key ___indicator of economic health.

酚酞是一种常用的酸碱指示剂。

Phenolphthalein is a common ___indicator for testing acids and bases.