。
She was wearing a strange hat.
Literal
She [topic-は] strange hat [object-を] was-wearing.
Japanese has an unusually rich set of 'wearing' verbs, each tied to a specific body part or article: 着る for shirts and dresses (upper body and full-body garments), はく for trousers and shoes (lower body), かぶる for hats and helmets (head), つける for accessories like watches and earrings, かける for glasses, する for ties and scarves. Where English uses 'wear' across the board, Japanese splits the verb by what's worn. かぶる literally means 'to cover' — putting something over the head — which is why it stretches to caps, masks, and even snow blanketing the ground (雪をかぶる).