Complex sentence: On 7 April 2014, U.S. Secretary of Defense Chuck Hagel became the first foreign visitor to take a tour of the "Liaoning" during a wider trip to China to discuss cybersecurity and address China's military buildup in the East China Sea.
Split into simpler sentences: On 7 April 2014, U.S. Secretary of Defense Chuck Hagel became the first foreign visitor to take a tour of the "Liaoning". The tour was part of a trip to China to discuss cybersecurity and address China's military buildup in the East China Sea.