A back may pertain-to a classroom.Logical formLearned from557 sentences. A back may pertain-to a man.Logical formLearned from545 sentences. A back may pertain-to a thigh.Logical formLearned from542 sentences. A back may pertain-to a camera.Logical formLearned from541 sentences. A (back yard) may pertain-to a male.Logical formLearned from540 sentences. A back can be broad.Logical formLearned from532 sentences. A back can be stiff.Logical formLearned from519 sentences. A back may pertain-to a shoulder.Logical formLearned from519 sentences. A male may arch a back.Logical formLearned from514 sentences. A back can be strained.Logical formLearned from513 sentences. A back may pertain-to a dress.Logical formLearned from510 sentences. A person may want a back.Logical formLearned from509 sentences. A back may pertain-to a hall.Logical formLearned from505 sentences. A male may lie on a back.Logical formLearned from500 sentences. A back may pertain-to hair.Logical formLearned from500 sentences.