Somebody tell me the usage of "in" "on" "with". Example1: Please don't hesitate in contacting me. Example2: I have progressed a lot in cooking. Example3: We need to spend more on advertising. Are they all correct ? in this kind of case, can this preposition be interchangeable? I am always confused about which one is more common/correct in spoken English.

Question about "whether" and "if". In spoken English Here is an example: "I don't care if your card breaks downs or not ?" Q1: Can this "if" be "whether" ? Q2: Is this "or not" neccessary? Can I just omit it ? Q3: Are they interchangeable? Thanks in advance.Sorry, I have typed a wrong word, in that example, "card" should be "car".

somebody tell me the difference between "ridiculous" and "ludicrous". somebody tell me the difference between "ridiculous" and "ludicrous". are they carry the same meaning? which is more common in spoken English?

Question about "kind of" Here is an example: "What kind of price do you expect the finished product to cost?" in this case, does "kind of" mean "rather" ? what does it exactly mean? I can't figure it out myself. please help.

Help me with this sentence. "I am dreaming of my little boy playing with his gone grandpa" (A) any wrong with the sentence? is this part "my little boy playing with his gone grandpa" followed by "of " too long ? Can I change it into: I am dreaming that my little boy is playing with his gone grandpa. ( B ) if both A and B are wrong , what would you say for the same meaning ?

question about 'kind of' Can we consider 'kind of' a a adverb ? someone tell me the difference between the two following sentence. A) I kind of found it hard to finish. B) I found it kind of hard of hard to finish. which is right ? if both are right, then which is more common in spoken English?

Preposition's problem. I am always confused about the use of 'in' and 'on' on some occasion. such as: be interested in be interested on any difference between them? Can you give more examples about 'in' and 'on' which might be easily confused for the beginner ? Thanks in advance.

Which is the right sentence ? I am wondering what you are doing now . I am wondering whare are you doing now . According to my knowledge, I would choose the first one. just like this example, "I don't know what love is" , it is wrong to say "I don't know what is love". Am I right?

Is there any difference where the nagative words be placed? I don't know if there is anyting wrong with my question. (if there is , please tell me) Here I have examples: I have no money. I don't have money. Nagative words have been placed in a different place. any difference between them ?