zài / jù zi / hái zi / zhèng zài / dú shū / zhōng / dú shū / chōng dāng / wèi cí / shuō míng / zhǔ yǔ / de / dòng zuò

在句子“孩子正在读书”中，“读书”充当谓词，说明主语的动作。

In the sentence “The child is reading,” “读书” functions as the predicate and describes the subject’s action.