when we use though and but?I think they have the same meaning...Thx

what's the difference between rather and too?Could you give me some sentences?Thx ~

Life is always like roller coaster? Whenever I complained the unfair treatment I have met and the bad feelings I have concealed deeply in my heart to my mom,she always said sanely:"Well,don't worry.Everything is gonna be fine.Life is always like roller coaster.Even now you are in the bottom,soon you could rise in the air at the break of dawn."Afer hearing that I felt peaceful,then i will go on my way confirmedly! Also like one Chineses movie"up in the wind" show,Sometimes you can't fly up high,it's not about you,it's just about the belated wind.Without the wind all the struggle are in vain. I trusted in those sayings,but this time,I'm too exhausted.In some sense,now i'm a totally loser and pessimist.I don't master the technique in my lab and my professor isn't satisfied with me.But the question is when i just enter his lab,how could he know i'm not competent in image processing ?just judged my ability by the first impression?And he don't give me the chance to choose my project.This kind of behavor isnot professional.He just gave me something he isn't familiar with,either.At the same time ,the other girl learn the prcessing .That is his strength.Above all, i feel uncomfortable because the unfair and undemocratic enviorment. The other problem is his words always hurts me,"You should do ....,why other can make it easily and fast,but you always meet the difficulity?"These words aren't useful to my project at all.They just make me doubt myself .So I can't stand this. I've been uncomfident and unhappy for 2 years.So when is the break of dawn.Sometimes I thought the worst thing I did was when I just graduated from my colleage,I don't know what's the meaning of research.At that time,I thought every chanlledge can be overcame if you work hard.So I choose the academic way.Yeah,You can achieve every goal,but the prerequisite is you have a strong mental quality to struggle in the high pressure situation,or just choose something you could achieve easily and happily! Don't embarrass yourself! Perhaps the break of the dawn will come when I make the proper choice by myself in the future.

Attendance is easier,while participation is more difficult! When I was a child,I started learning English.But at that time,my goal is to have a good score in my final,Actually I just learned dumb English.I could speak to others or to say, feel nervous to use English. But now,I have to talk to some foreign professors ,discuss some problems with them,listen to some research seminar,All these require my English good.Besides,I want to have a little international perspective and have my position in a multinational company in the future,So learning and practising are essential to me. To achieve my goal,I attend one training center,I have a lot of classes each week,I squeeze my time to avoid missing one class.But at class,I just get used to listening and taking notes.I did not participate it.Sometimes when I feel really happy,I could say some short sentence or some words.Most time,I don't want to say,and feel scared to speak.So I just made a small process.The biggest problem is i couldn't hear that clearly. Today,I feel a little frustrated,i attend a small party,called Friday Talk,some international students learn calligraphy with me,but i didn't talk too much,i feel I didn't attact them,or to say I'm boring.But one freshman ,good at calligraphy,make some friends as expected.Even i didn't praise others ,I 'm too lazy.How come?The reason is my character?I am too introverted?how can I change myself? I spend a lot of my time attending,but i feel i never enjoy it! What i should do is to think deeply and find the answer,but never give up. Remember your original intention!