阅兵 is a separable verb (离合词) meaning 'to review troops' or 'to hold a military parade'. The verb 阅 ('review') and the object 兵 ('troops') can split apart when inserting measure words, durations, or other elements — for example, 阅过一次兵 ('reviewed the troops once'). It's used for formal military ceremonies such as National Day parades. The word is compound, and unlike 'review troops' in English, it's a fixed phrase that's commonly used as a single lexical unit.