单词：precursors
n. a person who goes before or announces the coming of another
n. something that precedes and indicates the approach of something or someone
precursors的用法和样例：
例句
- Rare earth luminescence materials of alkaline earth stannates have also been prepared via thermal decomposition of hydroxo stannate precursors.利用某些新型带羟基的碱土锡酸盐作为前驱体，固相反应合成掺稀土的锡酸盐发光材料。
- The two cyclopentadienyl groups in metallocence compexes can be linked by one or two bridging groups to form ansa-metallocence catalyst precursors.摘要茂金属化合物中两个茂环可以通过一个或两个桥基相连接，形成各种桥联茂金属催化剂前驱体。
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