。
She does nothing but cry.
Literal
She [topic-は] cry [only-てばかり] is.
~てばかりいる is a fixed pattern for 'doing nothing but X / always X-ing,' typically with a tinge of complaint or resignation. It builds from the te-form plus ばかり ('only, just') plus いる, and it's almost always read as criticism — bemoaning that the subject does this excessively. Compare 泣いている ('is crying right now') with 泣いてばかりいる ('does nothing but cry, all the time'): the latter passes judgment. The grammar uses いる because of the ~ている base, but the meaning has drifted into habitual territory.