Before we answer, would you like to correct option 2! :)

1. "I am not sure I do it right when I train": General doubt about your usual training method. 2. "I am not sure I am doing it right when I am training": Doubt about your current training session. 3. "I am not sure I do it right when I am training": Uncertainty about correctness during a specific training session, with a slight habitual feel.

Here’s the difference in meaning between these sentences: 1. "I am not sure I do it right when I train." - Meaning: You’re unsure if your general approach or habit of training is correct. This focuses on how you train regularly (a repeated action). 2. "I am not sure I am doing it right when I am train." - Incorrect: This sentence has a grammatical error. It should be: "I am not sure I am doing it right when I am training." 3. "I am not sure I am doing it right when I am training." - Meaning: You’re unsure if what you are doing in a specific moment (during a particular training session) is correct. This emphasizes the action as it’s happening. 4. "I am not sure I do it right when I am training." - Meaning: You’re questioning whether your method is correct during your training sessions in general, combining an ongoing process (training) with a habitual issue (doing it right). Summary: - "I do it right when I train" = Focuses on regular, habitual actions. - "I am doing it right when I am training" = Focuses on a specific moment or ongoing process. Tip: Use simple present ("I do") for habits or general truths, and present continuous ("I am doing") for actions happening now or during a specific period.