Sometimes the data is split into parts to make the file sizes more manageable, although that 121 MB one is just a little larger than I've seen. The biggest one I've encountered so far is 108 MB.
When I looked at one of my files, there were over a million rows of data, but when I combined the two parts together, they came out to be the right number. So you should just be able to load both parts.
I don't know what software you're using so I can't provide guidance there. I've written some code to load the data into a MySQL database and I can just load both of them sequentially into the database without issues.