。
She had been crying the whole time.
Literal
She [topic-は] the-whole-time was-crying.
A bare past-progressive describing an ongoing emotional state. 泣く ('cry / weep / sob') is the everyday verb for crying, covering everything from a single tear to wracking sobs — Japanese pairs it with mimetics for finer texture (しくしく for quiet sobbing, わんわん for loud bawling, ぐすぐす for sniffly, めそめそ for whimpering). Without a mimetic the verb is neutral. ずっと extends the duration. The combination is plain and direct — no embellishment, just unbroken crying.