someone correct this letter, please

Subject: Inspection and Handover of the Project

Dear Mr. Takagi, Project manager,
We would like to inform you that we will finish the work including the additional work items by December 4, 2017, when we will be ready for inspection and handover of the project.

Sincerely yours.

Is this English practice or are you going to be actually submitting this letter?  You could also split the sentence into:

.. by December 4, 2017.  We will then be ready for ...

What is your favorite pastime?

The most  My favorite pastime is strolling along the river near my place. I often go out in the evening and think of the day's events. One day that when I had been angry, I took a walk to take it all in I and just relaxed and took a look back about what were facts and what was right, while walking. Another day that I had been pleased, I basked in the afterglow (afterglow of what?). By the way, walking has its benefits for keeping good spirits.

What is your favorite pastime?


Hi.

Overall good, I had to rearrange your second sentence as having the 'while walking' at the very end seemed odd.  Also, when talking about the afterglow,  you should indicate what the afterglow is for.  I assume for the good day, so you could say something like, I basked in the afterglow of the great day.