sign up
phrasal verbsign on/up | sign somebody on/up
to sign a form or contract which says that you agree to do a job or become a soldier; to persuade somebody to sign a form or contract like this （使）签约受雇（或入伍） He signed on for five years in the army. 他签了在部队服役五年的合同。 The company has signed up three top models for the fashion show. 为时装表演，公司签约聘了三名顶尖模特儿。
sign up (for something)
to arrange to do a course of study by adding your name to the list of people doing it 报名（参加课程） You can sign up online for language classes. 你可以在网上报名参加语言课程。