In English we talk about points in time. On a TV police drama, the inspector might ask, "At what point did you realize that the suspect had a gun?"
"Just before he entered the bank."

In Japanese, the same concept is expressed with ところ , generally "place". In this case it means a point in time rather than a point in space. I can easily make the translation if I remember what my boss used to ask me when he wanted to know my project status, "So. Where are you on this?" I had either just done V (Vta + tokoro [desu]), was just about to do V (V3 + tokoro [desu], or was in the middle of doing V (Vte + iru + tokoro [desu]).

As you can see, this builds on verb conjugation we've already learned: the plain non-past (たべる), the plain past (たべた), and the plain continous (たべている). Adding ところ emphasizes that you are just about to, just did, or are right in the middle of doing something.

I'll Do It -> I'm Just About to Do It

晩ご飯を食べる。I'll eat dinner.
晩ご飯を食べるところです。I'm just about to eat dinner.

I Did It -> I Just Did It

晩ご飯を食べた。I ate dinner.
晩ご飯を食べたところです。I just ate dinner.

I'm Doing It -> I'm Right in the Middle of Doing It

晩ご飯を食べている。I'm eating dinner.
晩ご飯を食べているところです。I'm right in the middle of eating dinner.

Our textbook (Yookoso!) translated this last one to "I'm in the midst of eating dinner." Although you might come across the word "midst" in a Victorian novel, I can't remember ever hearing anyone say it. We say "I'm in the middle of eating dinner." An old-timey Texan in a Hollywood movie might say "smack dab in the middle". Speaking of Texanisms, remember how to say "I'm just about to ..." Yep. In Texas, we say "I'm fixin' to ...."

More Sample Sentences

• 車を直すところです。I'm about to fix the car.
• 皿を洗うところです。I'm about to wash the dishes.
• 寝るところです。I'm about to lie down.
• 勉強しているところです。I'm studying right now.
• 大好きな番組を見ているところです。I'm in the middle of (watching) my favorite show.
• この部屋を掃除したところです。I just cleaned this room.