His rage and frustration 'expressed' [='showed, manifested'] 'themselves' as/in/through temper tantrums.
Her love of nature is 'expressed' [='shown, reflected'] in her paintings/music.
a room where nursing mothers can 'express' [='pump'] milk for their babies
(..) Darla! - What's wrong with her? - She wouldn't stop shaking the bag. - Poor Chuckles. - He was her present last year. Hitched a ride on the porcelain express. She's a fish killer. l can't go with that girl. l have to get back to my dad. - Daddy! Help me! - He's stuck. Nobody touch him. (..)2003 Finding Nemo