英文问号怎么标？

请问标准英文书写时，一句多问的情况问号需要每个问句后都标注吗？
比如这样一句话：When are you leaving, who is going with you, Why? 一句话三个问题，需要每个都标"?"，还是只在最后Why那里标一个问号，前面用逗号分隔。

When are you leaving? who is going with you? Why? 这句话三个问题，确实需要每个都标"?"，目的是为了加强语气。