。
She could only take a few hours of Japanese lessons.
Literal
She [topic-は] Japanese's class [object-を] [only-ほんの] [a few-hours-数時間] [only-しか] could-not-receive.
Two restrictive markers stacked. ほんの ('mere, just') quantifies 数時間 ('a few hours') as a small quantity. Then ~しか + ない ('only, just') restricts the verb to that quantity. ~しか~ない always pairs with negation, even though the meaning is exclusive rather than negative. 授業を受ける ('take a class') is the standard educational collocation.