How can I use "As" & "Since" with the meaning of "Because"? How can I use "As" & "Since" with the meaning of "Because"? Is it different when using "As" and "Since"?

A letter for my little boss It's appraisal interview but I am not happy at all. It's not because of the low increasing but you let me think a lots. You said that you're happy with what I did during past year and I proved that I can be a good auditor. But there are something that I don't think you were right. Also it's really sad when you said that you sometimes don't understand what I mean. Sorry I tried my best to let you understand but it's my fault, it's due to my poor English skill. There are something that you haven't satisfied on me. You told me it doesn't matter how many good thing we do but if we do the bad thing even though only once, people only remember bad thing we do. You proved it already. You can remember exactly twice when I caused mistakes but you don't remember how much I contributed. But it's okay I always take my responsibility whenever I cause mistake. You don't have to worry about this. Actually I had no pressure on the last mistake but I asked you because I worry you will leave due to affect from my mistake. Although I don't talk to you very much but I care much about you. Recently you give me a high pressure when you said that I have to be in a new role. It's a challenge for me but I am under pressure because you expect from me too much. I think my ability is not enough so you couldn't give me a change to join just a seminar. By the way I will effort more to be worth with your expectation. I don't know how long will be the time I still stay here but if I leave I am sure that the reason is not because of you.

A bit of feeling It's the first day of work in the new year. I was a little happy. But I don't know why I was still weak like that, why I could not be stronger when I heard his voice. But I really don't know why he knew how to choose the right time to contact me when I felt most lonely. People said that it's not important if you come first or not but it's important when you come at the right time. I wonder if that is important now. Why did I gently answer his phone call even though I had been painful so much? Why didn't I yell at him when I heard his voice? But what incivility can I do that? I am nothing to him. I understand it. But I keep asking myself like this until he will give me the answer because I am conflicted between heart and mind. Time is the answer, I think. However I am glad because he still remember me and want to meet me. That's enough now.

My journey My desire is travelling to everywhere in Vietnam and other countries to see the people and places. I'm in the progress of making my dream come true. The first trip was going to Dak Nong province, a highland area. The trip was only 2 days but there are much feelings. The town is very small, named Gia Nghia. There is nothing special here expect for hills and forests, basic factors of highland area. And I like it. However I like the hills with the pine trees at Dalat more.But for this year I haven't gotten the change to go there. At Daknong there is one food called meat of forest animals that I think it’s very special. I ate forest pork, deer and one special animal that I don’t know. However my boss is afraid of eating these animals. Poor her… Anyway she is so lovely in her way. In the next morning, I was so shy in front of her. Because she told me to get out of hotel at 7:00 am. Although I got up at 6:30 am but I was lazy to get out of my bed so I continued sleeping. Then I received a message from her: Are you ready? While I was replying her, the door bell was rung. Oh my god, I told to myself. I already knew who was ringing the bell. I got out of my bed and opened the door. I frozen for a while and after that she smiled at me. I smiled back with a flushed face of shame and asked for 15 minutes more. Then I had to get out of my bed and got ready for work. Anyway I love to go on business trip except for preparing reports after coming back from the trip. But it’s okay. I can manage to write a report which enough for my boss to understand although it’s not academic report…

The book which i like best the book named "伤心致死", the writer is 鬼谷女. it's the best book i have read.<img alt="" src="http://www.italki.com/fckeditor/editor/images/smiley/msn/thumbs_up.gif" />