I was asked to take on the a big project from by the board member. I said that I needed to more time to contemplate it before I answered answer it.

Finally, even though it was a big chance for me, I declined this proposal because I has have been involved in another work and I was dedicated to finalize it. Moreover, I have to make step-up my work step-up. One of my co-workers who heard that news told me that who would say no to him except for you.

REVISED:

I was asked to take on a big project by the board member. I said that I needed to more time to contemplate before I answer it. Finally, even though it was a big chance for me, I declined this proposal because I have been involved in another work and I was dedicated to finalize it. Moreover, I have to step-up my work. One of my co-workers who heard that news told me who would say no to him except you.

Hi Tony,

This is new since you got some expressions from YouTube, it's excellent! As you can see, I just made some changes and most importantly, added appropriate punctuations and capitalize words that needed to be written like that because when we compose something, you should also be aware of that since you might also make emails, letters etc. Thanks for this,  I hope we you could get more expressions and broaden your knowledge bout these.

Teacher Neiz