sign up
phrasal verb with sign verb uk/saɪn/ us/saɪn/
B1 报名参加（某项有组织的活动）
to agree to become involved in an organized activity
[ + to infinitive ] I've signed up to make the sandwiches for the party. 我已报名为聚会做三明治。
She's signed up for evening classes at the community college. 她已经报名参加社区学院夜间课程的学习。
See also: sign on (AGREE TO HELP)