Future: typical errors

We don’t use the present continuous when we predict something:

• You’re going to fail the exam unless you attend more classes.
• Not: You’re failing the exam, unless …

When we make an immediate decision, we use ’ll not will or shall or the simple present tense:

• Wait a minute, I*’ll** lend you my car.*
• Not: … I shall lend you my car. or … I lend you my car.