An appearance can be hollow.Logical formLearned from18 sentences. A (fiber membrane) can be hollow.Logical formLearned from18 sentences. Plastic can be hollow.Logical formLearned from18 sentences. Cells can be hollow.Logical formLearned from17 sentences. A sort can be hollow.Logical formLearned from17 sentences. A fly can be hollow.Logical formLearned from17 sentences. A limitations-auric can be hollow.Logical formLearned from17 sentences. (Crew teams) can be hollow.Logical formLearned from17 sentences. A cough can be hollow.Logical formLearned from17 sentences. A pain can be hollow.Logical formLearned from17 sentences. A male can be a hollow man.Logical formLearned from17 sentences. A body can be hollow.Logical formLearned from17 sentences. Stalks can be hollow.Logical formLearned from17 sentences. A design can be hollow.Logical formLearned from17 sentences. A (metal sphere) can be hollow.Logical formLearned from17 sentences.