Modifier consists of the preceding modifier and the following subject. The subject can be either a verb or an adjective. The former part is the phrase type that complements the latter part. In this phrase, "Jiang Yue" is a complement to the subject "Ying Hui" and explains the form of "Ying Hui", so it is a partial phrase. Similar phrases: mutual harm, mutual care, exchange of needed items, etc.
The shadow of the moon on the river describes the beautiful scenery of the moon shining on the river. It is a common descriptive technique in China ancient literature, which embodies the author's rich imagination and language art. It is widely used not only in poetry, but also in painting, calligraphy, music, drama and other art forms.