private Tuple<Annotation,Boolean> findSentence(Tuple<BigInteger, BigInteger> goal) {

		ListIterator<Tuple<Annotation,Boolean>> senIter = sentences.listIterator();
		Tuple<BigInteger, BigInteger> currTuple = null;
		Tuple<Annotation,Boolean> currSen = null;

		while (senIter.hasNext()) {
			currSen = senIter.next();
			currTuple = new Tuple<BigInteger, BigInteger>(
					currSen.x.getStartNode(), currSen.x.getEndNode());
			if (currTuple.x.longValue() <= goal.x.longValue()
					&& currTuple.y.longValue() >= goal.y.longValue()) {
				senIter.remove();
				Tuple<Annotation,Boolean> sentencePos = new Tuple<Annotation,Boolean>(currSen.x, Preprocessor.pos);
				sentences.add(sentencePos);
				return currSen;
			}
		}
		return null;
	}