host occurrence of silver的用法和樣例：
例句
- The occurrences of vanadium are mainly in adsorption and isomorphism states.
釩的賦存狀態主要有吸附態和類質同象態。 - Occurrences of organic matter in Paleogene argillaceous rock of Jiyang depression are primarily studied by means of fluorescent microscopy.
應用熒光顯微鏡法，首次對濟陽坳陷下第三系泥質岩中有機質的賦存狀態進行了研究。
