Hi. In a test I'm asked to find out something 'strange'/unusual in this sentence from the novel "Princess Hannah" by Jerome Charyn: "Harrington had his own silent poetry - the deep sadness in his face - but that wasn't enough." They gave me no further context or explanation, only that the sentence is 'grammatically correct'. Is it about the preposition 'in' instead of 'on'? I can't notice any other 'unusual' form, but I'm still not sure about it. Could someone be helpful? Thanks.