Original: Under Qing pressure, Zheng Jing struggled to defend Xiamen, Quemoy and the Pescadores islands, which he had eventually lost over the years, mainly due to his minuscule forces which were insufficient to defend from the Qing.
Simplified: Zheng Jing fought the Qing to defend Xiamen, Quemoy and the Pescadores islands, which he finally lost over the years.