I will appreciate your assistance in translating the following expressions (I tried to translate them below). The expressions are random and they mainly include some grammatical points that are not so clear to me, such as the use of Творительный and some problems with падеж of Numbers (Currently I am not interested so much in understanding full the grammatical I just want to see which are the correct forms) .


1. I have regretted leaving England so early
2. Where is George? He has disappeared for two weeks.
3. Before one month he introduced me to a very good customer.
4. I started dating with her but after the first two meetings I understood that she was not so clever.
5. She was proven not to be so clever.
6. If I haven’t insist I wouldn’t now be in Russia with two new offices (i.e. I wouldn’t have open two new offices in Russian despite the difficulties).
7. They client you introduced to me a while ago in this office seems extremely interesting.
8. She is so stubborn that you cannot speak with him without losing your temper.
9. The harder you work the most successful you will be.
10. In order to save time I have translated them alone.
11. I am so excited today. I passed my exams.

In order to save some time I tried to translate them alone:
1. Я сожалел что я уехал из Англии так рано - I don't think that сожалеть is the correct verb
2. Где Джордж?Он пропал на две недели - I also find the word исчезать
3. После одного месяца он познакомил меня с хорошим (крупным) клиентом.
4. Я начал (стал) встречаться с ней но после первыx двух встреч я понял что она не была такой умной - The Творительный at the end is more based on reflexives rather than deep knowledge of grammatical
5. Онa оказалась / доказалась не такой умной - Big confusion with these two verbs. I know that доказать is the verb used in mathematics. Also Творительный is used on a reflexive way
6. Если бы я не настаивал я не был бы в России сейчас с двумя новыми офисами.
7. Клиент, с которым Вы познакомили меня время назад в этом офисе выглядит / кажется очень интересным. - Confusion with выглядит / кажется
8. Он столь / такой упрям что нельзя раговоривать с ним не ... - The use of столь / такой bothers me. Also the use of kratkaya forma in the case of упрям makes me wonder.
9. Чем больше работать тем больше успешным ты станешь - The issue here is not the structure чем ... тем rather the decision what person to use. I tried to use an impersonal construction but obviously I failed.
10. ???
11. ???

Thank for your time