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
(..) It will be sold by tuesday night. Can we go? You've been staring at this for an hour. You're gonna have to change the channel at some point. This painting expresses an overwhelming serenity. And some violence as well. I find it very moving. Red stains on a white background are moving? (..)2011 The Intouchables