1. I want to learn what car to drive.
2. I want to learn which car to drive.
3. I want to learn how to drive a car.
4. I want to learn that I can drive a car.
5. I want to learn who to drive.
6. I want to learn whom to drive.
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Which ones are ungrammatical? Would you correct errors? Thank you.
1 is okay, 2 is better. 3 is good, 4 is not. 5 & 6 don't quite make sense. Do you mean a passenger you will drive somewhere? A car is not a "who" or "whom", it's a "what" or "which". If it is a passenger, 6 is correct.
Out of the six statements you provided, there are two that contain grammatical errors. Let's go through each one and address any errors or corrections needed:
1. I want to learn what car to drive.
This sentence is grammatically correct and does not require any corrections.
2. I want to learn which car to drive.
This sentence is also grammatically correct and does not require any corrections.
3. I want to learn how to drive a car.
This sentence is grammatically correct and does not require any corrections.
4. I want to learn that I can drive a car.
This sentence is grammatically correct and does not require any corrections.
5. I want to learn who to drive.
This sentence contains a grammatical error. It seems like you might be trying to ask who can drive, in which case the correct sentence would be "I want to learn who can drive."
6. I want to learn whom to drive.
This sentence also contains a grammatical error. It is not clear what you are trying to ask, but if you want to learn whom you can drive (in a sense of chauffeuring someone), a more appropriate sentence would be "I want to learn whom I can drive."
So, out of the six statements, only the last two contain grammatical errors. I have provided the correct versions of those statements based on my understanding of what you might be trying to convey.