A ball can be hollow.Logical formLearned from5 sentences. A sentimentality can be hollow.Logical formLearned from5 sentences. A stalk can be hollow.Logical formLearned from5 sentences. Mountains can be hollow.Logical formLearned from5 sentences. A courtesy can be hollow.Logical formLearned from5 sentences. Blanks can be hollow.Logical formLearned from5 sentences. A fault can be hollow.Logical formLearned from5 sentences. A (gravity dam) can be hollow.Logical formLearned from5 sentences. A sculpture can be hollow.Logical formLearned from5 sentences. A display can be hollow.Logical formLearned from5 sentences. A bass can be hollow.Logical formLearned from5 sentences. An effect can be hollow.Logical formLearned from5 sentences. Demands can be hollow.Logical formLearned from5 sentences. A disc can be hollow.Logical formLearned from5 sentences. A (drill bit) can be hollow.Logical formLearned from5 sentences.