A (dog pen) can be empty.Logical formLearned from11 sentences. A person may write with a pen.Logical formLearned from11 sentences. Pens can be biodegradable.Logical formLearned from11 sentences. A blade may turn into a pen.Logical formLearned from11 sentences. Pens can be for a rower.Logical formLearned from11 sentences. A pen can be in hand.Logical formLearned from11 sentences. A US-president may wield a (veto pen).Logical formLearned from11 sentences. A back end may pertain-to a pen.Logical formLearned from11 sentences. (Pen mates) may pertain-to a male.Logical formLearned from11 sentences. Fish can be in pens.Logical formLearned from11 sentences. Pens can be sharp.Logical formLearned from11 sentences. A (pen pal) can be constituted-of-or-filled-with serial killers.Logical formLearned from11 sentences. A person may become a (pen pal) of serial killers.Logical formLearned from11 sentences. A pen may pertain-to an editor.Logical formLearned from11 sentences. A pen can be in a mouth.Logical formLearned from11 sentences.