Jambo moja ambalo nadhani alipaswa kusisitiza zaidi ni kwamba concatenation na lugha tupu inakupa lugha tupu. Kisha inakuwa dhahiri kwa nini hapana mshale ni sawa na neno tupu. mshale na na lugha tupu.####[['NULL', 'Instructor', 'NEG'], ['concatenation', 'Mathematical_Related_Concept', 'NEU'], ['lugha tupu', 'Mathematical_Related_Concept', 'NEU'], ['mshale', 'Mathematical_Related_Concept', 'NEU']]