@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (!(obj instanceof Sentence))
			return false;
		Sentence other = (Sentence) obj;
		if (sentence == null) {
			if (other.sentence != null)
				return false;
		} else if (!sentence.equals(other.sentence))
			return false;
		return true;
	}