sign up to

phrasal verb
1
to commit yourself to a project or course of action, especially one that you have agreed with a group of other people, countries or organizations
ثبت‌نام کردن, متعهد شدن
2
to agree to take part in something
ثبت‌نام کردن, عضو شدن, نام‌نویسی کردن
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