A leader can be alien.Logical formLearned from69 sentences. An object can be alien.Logical formLearned from68 sentences. A problem can be alien.Logical formLearned from68 sentences. Students can be alien.Logical formLearned from68 sentences. Parents can be alien.Logical formLearned from67 sentences. (Plant species) can be alien.Logical formLearned from67 sentences. An army can be alien.Logical formLearned from67 sentences. A weapon can be alien.Logical formLearned from66 sentences. Terrorists can be alien.Logical formLearned from66 sentences. A sky can be alien.Logical formLearned from65 sentences. A mothership can be alien.Logical formLearned from65 sentences. A (space ship) can be alien.Logical formLearned from65 sentences. Individuals can be alien.Logical formLearned from63 sentences. A society can be alien.Logical formLearned from63 sentences. A plant can be alien.Logical formLearned from62 sentences.