Jack is the ______- child in the family; he wants to have a brother.

She sat at her desk，with her eyes ________ on the book，________ in its plot.

This bird is really lovely, and I’ve never seen ________ one. 

Would it be ___ for you to pick me up at four o’clock and take me to the airport? 

Lawmakers have approved the measures_____ protecting the personal information of Web users.