A Special Sunday School Lesson

Each week I sit through sacrament meeting and Sunday school getting very little.  I can pick out words here and there, but really don't understand much.  I've developed some coping methods:  Every other week, I play the organ and that helps me a lot on those days.  I read a conference talk or scriptures during the meetings, I get "healthy sleep" as President Uchtdorf suggested, I have the sacrament prayers memorized, so I always say them to myself while they are being said in Japanese.  I get by. 

A couple of weeks ago, sweet Mami (a young single adult in the branch who has been called to be one of the gospel doctrine teachers) came up to us after sacrament meeting and asked if we would sit on the front row during Sunday school class.  She was teaching that day.  We didn't know what she wanted, but we complied.  She started her lesson, and we soon realized why.  As she said each thing in Japanese, she held up a sheet of paper that had a translation of what she was saying in English.  Mami speaks no English.  She had spent hours using a digital translator to prepare this for us. 

The translation wasn't perfect, but it gave me an idea of what was going on. 

It was such a kind, thoughtful, Christ-like thing to do for us.  I was so very touched.  Later, in Relief Society, Mami's mom said (Sister Hirayama translates Relief Society for me) that Mami had been up until five a.m. that morning preparing her Sunday school lesson. 
How do you express gratitude when someone sacrifices so much for you?  I don't know either.