Groups of Hong Kong students on Friday had a lesson aboard two PLA Navy warships moored at Stonecutters Island’s Ngong Shuen Chau Barracks on Friday.They toured guided-missile destroyer Nanning and guided-missile frigate Hengyang, which arrived for a five-day port call that started on Thursday.The port call marked the 29th anniversary of the city’s return to Chinese sovereignty on July 1.Pui Kiu College student Jas Xu said stepping into the ship cabins and observing the interior weapon...