Complete the frustrated roommate's text message.

You __________ in the shower for forty-five minutes! Are you trying to wash away your sins, or just all the hot water?

The correct answer is have been singing.

We use the Present Perfect Continuous (have/has been + verb-ing) to talk about an action that started in the past and is still continuing right now, especially when we mention how long it has been happening (using "for" or "since").

"Are singing" (Present Continuous) is incorrect because it doesn't account for the duration ("for forty-five minutes").