protected boolean isTrue(Stream seekable) {
		if (!this.skip(seekable)) {
			raise(new JsonParseException("prase boolean value 'true' fail,unexpected eof", this.excpetion()));
			return false;
		}

		if ((consume(seekable, 'T') || consume(seekable, 't')) //
				&& (consume(seekable, 'R') || consume(seekable, 'r')) //
				&& (consume(seekable, 'U') || consume(seekable, 'u')) //
				&& (consume(seekable, 'E') || consume(seekable, 'e'))) {
			return true;
		}

		return false;
	}