Task: Pos Tagging
Input (English): Sentence: In all the above procedures , when the intermediate {{ sera }} were diluted to 1 : 10 or 1 : 100 with 0.85% saline , the specific and nonspecific fluorescence were not appreciably reduced , whereas , a dilution of the intermediate sera to 1 : 500 or diluting the Af to 1 : 5 greatly reduced specific fluorescence . 
Word: sera
Output (English): NOUN