Hey Ramin, I shall review the sentences you provided: 1) Please let me know if there is no difficulty WITH? or FOR? you. = this is not correct! It should be rewritten as either ''Please let me know if there are any difficulties for you'' or ''Please let me know if you find yourself in difficulties''. 2) I will provide you with a good product. = that is absolutely correct! :) 3) How long does it took to get to your house? | How long did it take to get to your house? = The first sentence should be rewritten as ''How long does it take (for you) to get to your house?''. As for the second one, it is perfectly fine! 4) Please say him go. Please say to him to go. = I dare say it sounds rather awkward. I would advise you to change it to ''Please tell him to go''. Hope that helps!!! Should you have any further questions, do not hesitate to contact me. I shall be pleased to help.

Please let me know if there is no difficulty WITH? or FOR? you. WITH - you are together with the person. FOR - you are doing something for the person. I will provide you A good product. --> Don't use WITH in this case How long does it took to get to your house? | How long did it take to get to your house? How long does it TAKE to get to your house - Simple Present, it's a routine. How long did it take to get to your house? - Simple Past, specific event in the past. Please say him go. --> not ok Please say to him to go. --> ok, but not really. Instead, go for "please, tell him to go"

Correct: I will provide you with a good product. Correction: How long does it TAKE to get to your house? Correct: How long did it take to get to your house? Correction: Please TELL him to LEAVE. or Please tell him to go (away). (Unless you are asking him to speak that exact word, "Please say, the word "GO" to him.) Hope this helps

Thought this was part of your question: Please let me know if there is no difficulty WITH? or FOR? you Here the sentence would be ‘please let me know if you have any difficulty (with it)’

The issue here is with the last two, where you should use ‘tell’ instead of ‘say’, and reframe the sentence: ‘Please tell him to go’ You can use say to convey instructions via a third party, e.g ‘say to him that I will wait for his answer’, but where it is an instruction, like ‘go’, tell is the only option between the two words. Also take instead of ‘took’, as Naomi said.