Complex sentence: The 5th corps is the most elite unit in the NRA, and it is also the only Chinese unit had tanks and armored vehicles, its soldiers were combat-hardened veterans from previous battles against the Japanese troops and morale were high.
Split into simpler sentences: The 5th corps is the most elite unit in the NRA, and it is also the only Chinese unit that had tanks and armored vehicles. Its soldiers were combat-hardened veterans from previous battles against the Japanese troops and morale were high.