def get_ngram_pos(toks, key_indx):
    """
		Given ngram: 'convention center'
		
			found at index: 13 
			in this sentence: at the brown convention center
			sentence toks: ['at', the', 'brown', 'convention', 'center']

		The purpose of this function is to return sentence toks index: 3
	"""
    offset = 0
    for i in range(len(toks)):
        if offset == key_indx:
            return i
        offset += len(toks[i]) + 1
    return -1
