EXERCISE 23–4 Pronoun reference
Example:

When young Polynesians were exposed to Western standards of beauty, it made them self-conscious about their weight.

Young Polynesians who were exposed to Western standards of beauty became self-conscious about their weight.

In the second sentence, all pronouns refer to clear antecedents. In the first sentence, the pronoun it has no clear antecedent.

For more help, see section 23.