My first work unit was in a county which wais located in the mid-east part of Anhui Province.

The County has not moved, so you would use the present tense.

My second work unit was in the city l live in nowwhere l currently live, and it was also with somehad bungalows.

My third work unit was also in the same city and it only had three or four rooms.

My fourth work unit was located in the same place as the second one, but when I returned there, it had added three buildings.

My fifth work unit is the current one, and Finally, out of all the units that I've ever worked in, my fifth and current work unit ihas the most modern one I have ever worked in.facilities.

It is in a tall and modern office building.

The decorations are very luxurious, buyet I still prefer to work in the fourth work unit because it hasd a big yard, so I can go to the yard toallowing me take a breaks outside and breathe somin the fresh air.

My first work unit was in a county which was located in the mid-east part of Anhui Province.

I'm not sure what you mean by work unit. Maybe "workplace"? or "The first office I worked in".

Our work place was on a small hillside with several rows of bungalows.

My second work unit was in the city l live in now, and it was also with somesurrounded by bungalows.

My fourth work unit was the same as the second one, but when I returned there, it had addedwent back, three new buildings had been added.

My fifth work unit is themy current onworkplace, and it is the most modern one I have ever worked in.

The decorations are is very luxurious, but I prefer to work inred the fourth work unit because it hasd a big yard, so I canould go to the yard to take a break and breatheget some fresh air.