、。
She's been practicing piano since this morning.
Literal
She [topic-は] morning [from-から], piano [possessive-の] practice [object-を] is-doing.
朝から ('since this morning') marks the starting point of an ongoing action. ピアノの練習をしている ('is practicing piano') uses ~ている for an action still in progress. The comma after から gives a slight pause, highlighting the duration — she started this morning and is still at it.