; (4) the United States should improve the predictability of arms sales to Taiwan by ensuring timely review of and response to requests of Taiwan for defense articles and defense services; (5) the Secretary of Defense should promote Department of Defense policies concerning exchanges that enhance the security of Taiwan, including— (A) United States participation in appropriate Taiwan exercises, such as the annual Han Kuang exercise; (B) Taiwan participation in appropriate United States exercises; and (C) exchanges between senior defense officials and general officers of the United States and Taiwan consistent with the Taiwan Travel Act ( Public Law 115–135 ); (6) the United States and Taiwan should expand cooperation in humanitarian assistance and disaster relief