I agree with Peachey. If I may be permitted to add some further help with question 3: I would suggest you rewrite your sentence like this: "I envied my friends then. Each of them had a kite of their own. Their parents always too them kite-flying at the playground." Please try to understand the vocabulary and the constructions, and ask us if there is anything you don't understand. The important thing is you should try the explanations from online dictionaries and grammar guides first, so that you go through the real search-and-learn process. I can see your enthusiasm for learning English. To succeed, I think you need: 1. an English course with homework of an appropriate level that you have to attend regularly; 2. a good native English teacher; 3. a good English-English dictionary, such as the Oxford Advanced Learner's Dictionary; 4. a fixed time every day for revision and homework. You also need to read more. I can see that you are still thinking on Chinese. If you read more, you will start thinking in English. When you start thinking in English, your English will rapidly improve. Good luck!

1. She has this problem, but she sees it as a temporary situation. "I've been to the library" means she went there, and came back. These are two different pieces of grammar. 2. Really, not much difference when the action follows "start". It's very different with other verbs, such as "try", "stop" and "remember"! 3. Use "because", not "cause". These are two different words. Beware of this learner mistake. I'd use "each of them owned one as well". You need the past tense of "take", and it's easier to write "to go kite-flying" instead of deciding on "it/them"