In this case, the action is completely in the past (i.e., pollution levels in the 1900s are necessarily not the same as they are now, so that status has ended), so you'd use "to have been" which suggests that the condition no longer exists. In this case, it's kind of like the way you'd use 了.

In the US, we don't use the word at all, except possibly as a toast when drinking. Even then, it's not commonly used here.

As to studying characters, the most important things that helped me were to focus on stroke order and learn radicals. It seems unnecessary, but you'll find that once you do this, you're less likely to forget a stroke here or there. The closest equivalent would be to learn the alphabet before trying to learn words in English. As to looking up words in a dictionary, many dictionaries have pinyin, but if you have the character and don't know how it's pronounced, then you'll generally look it up either by radical or stroke count. (Both of these are good reasons to learn stroke order, since you might think that 口 has 4 strokes since it has four sides unless you knew that the second stroke contains two of the sides--I can't tell you how many words I've failed to look up as a result of miscounting the number of strokes.)

I'd say it's more embarrassing to be a virgin who didn't graduate from high school. After all, only a few people will know if you're a virgin, but everyone will know whether you graduated.

Another, somewhat fun, answer to the question is Hot For Music's analysis of the whole song: http://www.youtube.com/watch?v=sQah2-sO-_Q

Hi Jocelyn, Visa intake means receiving and processing visas for people who want to visit the country. (That is, you'd expect to receive the passport, run background checks if needed and prepare the visa documentation.) Data entry means typing information into a computer, most likely a database. Data processing is likely similar to data entry but may involve some analysis of the data. Tony

Pls help me correct my composition

I want t<strike>o be a </strike>volunteer <strike>for</strike> to helpi<strike>ng</strike><strike> someone </strike>people in need, so I called the office of a retirement home today. But the person who answered <strike>answering</strike> the call <strike>was so rude.She</strike> rudely told me that, while they need some volunteers, <strike>but</strike> they don't have a big volunteer program. I told her I just want help their residents. She said that she was very busy and <strike>let me</strike> that I should come to her office to talk about it.<strike>then</strike> She then hung up<strike>rang off</strike> quickly without leaving me either the adress <strike>and</strike>or even her name.