A (spherical structure) can be hollow.Logical formLearned from2 sentences. (Glass fibers) can be hollow.Logical formLearned from2 sentences. Optical fibers can be hollow.Logical formLearned from2 sentences. An apology may sound hollow.Logical formLearned from2 sentences. A hollow body can be tubular.Logical formLearned from2 sentences. A hollow body can be with some supports.Logical formLearned from2 sentences. (Toad effigies) can be hollow.Logical formLearned from2 sentences. A triumph can be hollow.Logical formLearned from2 sentences. A debate can be hollow.Logical formLearned from2 sentences. Pens can be hollow.Logical formLearned from2 sentences. A reassurance can be hollow.Logical formLearned from2 sentences. Some totalitarian regimes can be hollow.Logical formLearned from2 sentences. (Plastic spheres) can be hollow.Logical formLearned from2 sentences. A closure can be hollow.Logical formLearned from2 sentences. Blobs can be hollow.Logical formLearned from2 sentences.