I want to know from a grammatical point of view why do we use be with will instead of using is and are. For example:
- Jack will be skydiving tomorrow. Correct
- Jack will is skydiving tomorrow. Incorrect
I also want to know why do we use is, are, was, and were instead of be in the present and past tenses. For example:
Present Tense
- Jack is skydiving today. Correct
- Jack be skydiving today. Incorrect
Past Tense
- Jack was skydiving yesterday. Correct
- Jack be skydiving yesterday. Incorrect