For ongoing actions:
* Je vais: This literally means "I go" but it's used to describe an ongoing action.
* Je suis en train d'aller: This means "I am in the process of going" and emphasizes the action is happening now.
For past actions:
* Je suis allé/allée: This means "I went" and is used for a completed action in the past.
* J'ai été en train d'aller: This means "I was in the process of going" and describes an ongoing action in the past.
Examples:
* Je vais au cinéma. (I am going to the cinema.)
* Je suis en train d'aller travailler. (I am in the process of going to work.)
* Je suis allé/allée au restaurant hier. (I went to the restaurant yesterday.)
* J'ai été en train d'aller à la plage tout l'après-midi. (I was in the process of going to the beach all afternoon.)
Remember: Choose the correct tense based on the context and whether the action is ongoing or completed.