Each of these contain many <e1>modules</e1> on different topics, such as <e2>apostrophes</e2>, silent letters, personal pronouns, spelling plurals, etc.
Each of these contain
Each of these contain many modules on different topics, such as apostrophes, silent letters, personal pronouns, spelling plurals, etc.
<triplet> modules <subject> apostrophes <object> Message-Topic(e1,e2)