"Register" 的短语是 "Sign up"，来源是英语中常用的词组。
例句：
"Please sign up for our website to get started."
"请在我们的网站上注册以开始使用。"
"I just signed up for a new onpne course."
"我刚刚在线注册了一门新课程。"
"To join the club, you need to sign up and pay the membership fee."
"加入俱乐部需要注册并支付会员费。"