Complex sentence: Based on Reinhart's theory, the pronouns in group (20) can all be coindexed within their respective sentences, however, the pronouns in group (21) are unable to be coindexed because none of the sentences meets the coindexing conditions.
Split into simpler sentences: Based on Reinhart's theory, the pronouns in group (20) can all be coindexed within their respective sentences. In contrast, the pronouns in group (21) are unable to be coindexed because none of the sentences meets the coindexing conditions.