US Secretary of State Rex Tilleson has stressed that the missile attack on Syria is also a warning to North Korea. In addition, the US Navy also announced that the USS Carl Vinson has changed the course and is heading for the West Pacific, which is a prudent measure aimed at maintaining the state of alert and presence at the West Pacific Ocean. In this regard, we must point out that the US Navy has shown extraordinary tough stance on North Korea; in fact this is also a message to China, and can be considered as a way for the United States to test China's bottom line. If the DPRK problem is resolved, this would mean that the situation in East Asia is completely subversive. China needs to be prepared in advance.