Final answer:
The example sentence is an understatement, a figure of speech that presents a situation as less significant than it is, commonly used for irony or humor.
Step-by-step explanation:
The sentence "I see the trash still hasn't been taken out" is an example of an understatement. An understatement is a figure of speech used to make a situation seem less important than it actually is, often for ironic or humorous effect. In this case, the speaker is downplaying the fact that the trash has not been taken out, possibly to highlight a point about a lack of responsibility or action in a subtle manner.