This study aims to examine the distribution of English unstressed pronouns, i.e., unstressed personal pronouns. English unstressed pronouns sometimes have a unique distribution different from their referential counterparts in phrasal-verb constructions, dative constructions, subject-verb inversed sentences, etc. This study shows that their unique distribution is due to the two properties that they have. One is that they are old in information structure, thus they choose to come earlier if possible in a sentence. The other is that they are clitic in that they are phonologically bound to their preceding Case assigner.