the usage of the subjunctive mood In the following phrase, which is correct, "what you did" or "what you had done" you will behave as if you didn't have to hake responsibility for what you did/had done. Thank you in advance.

The use of "improve" Does it make sense to say "improve traffic jams" or "improve environmental problems"? Can 'improve' mean 'ease' or 'solve'?

Which do you like more A or B? I learned the following sentence at school. Which do you like better,cats or dogs? But should the 'better' be replaced with 'more'? How about the answer to the question: I like cats better. I like cats better than dogs.

Native speakers, why do you use 'better' for the verb 'like'? I like sushi better than tempura. I love sushi more than tempura. I think you usually use 'better' when you say you prefer something to something else. However, you seem to use 'more' with the verb 'love', even though 'like' and 'love' are not very different in meaning. Could anyone tell me why?Thank you. But don't you say: Which do you like better, sushi or tempura? I like sushi better. We learn sentences like these at school.

Please help me to understand an English sentence If you're an Internet service provider (ISP), you may find that effective anti-spoofing, together with other effective security measures, causes expensive, annoying problem subscribers to take their business to other providers. Does "expensive, annoying problem subscribers" means "demanding, troublesome, and problematic customers"? And " take their business to other providers" means "(the customers) move their business to your competitors"?Thank you very much, but I am rather perplexed because even native speakers seem to interpret this sentence differently. This sentence was quoted from a Cisco's document: https://www.google.co.jp/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CDAQFjAA&url=ftp%3A%2F%2Fftp-eng.cisco.com%2Fcons%2Fworkshops%2Fisp-workshop%2FStudentCD-Rev-E%2FWhitePapers%2FImprovingSecurity.pdf&ei=Cr-7UfqlD4akkgWq4oCwBA&usg=AFQjCNEDOEeOvLn_htnOu91gY-2HIOfUjQ&sig2=f0KN16KljSL0hCjmKgoA_A&bvm=bv.47883778,d.dGI

the use of 'this month' in the present perfect tense I believe the following sentence is correct. I have arrived in the USA today. This is maybe because 'today' includes the present moment. However, the following sentence seems to be considered wrong although 'this month' naturally includes the very present moment. Why? I have arrived in the USA this month.

Is the phrase "deal in car insurances" incorrect? XYZ corporation have been dealing ( ) car insurances for over 30 years. I chose 'in' to fill in the brackets in this problem, but the answer turned out to be 'with'. Can't 'in' be a possible answer?Thank you Lao Kou-san, Do you mean 'car insurances' should be singular when using 'deal in', while it can be left plural when using 'deal with'?