1. Change the imperative sentences into more polite expressions beginning with "Do you mind if..."

2. When I say a sentence, you should say a more polite sentence beginning with 'Do you mind..."

3. _________________________________

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Are they grammatical? Do you have better sentences?

1 is fine.

2 is a little confusing because of the shift from "I" to "you." I'd just skip the first part and start with the word "You ... "

Other ways to soften the imperative --
"Would you please ... ?"
"Please make sure you ... "
or simply "Please ... "

1. Sure! Here are some examples of changing imperative sentences into more polite expressions using "Do you mind if...":

- Original: "Pass me the salt."
Polite: "Do you mind if you pass me the salt?"
- Original: "Close the door, please."
Polite: "Do you mind if you close the door, please?"
- Original: "Turn off the lights."
Polite: "Do you mind if you turn off the lights?"

2. Absolutely! When you say a sentence, I can provide a more polite alternative using "Do you mind...":
- You: "Give me the remote."
Me: "Do you mind giving me the remote?"
- You: "Please move your bag."
Me: "Do you mind moving your bag, please?"
- You: "Stop talking so loudly."
Me: "Do you mind stopping talking so loudly?"

3. To provide better examples, it would be helpful if you could provide specific sentences for me to work with.