薬の効果が無いとき:
It didn’t work
It wasn’t effective

二日前の夜:
two nights ago
couple night ago

Singular : 1
Plural : many

maybe : 30%
must : 75%

特定の:
particular
specific

もう充分:(充分遊んだ、充分食べた)
had enough

gathering = small party

子供のギターコンサート:
We went to KK’s concert. It was a 26-member orchestra.
KK was the 3rd player. I recorded her performance with my camera.
She played the guitar about 5min.
We wanted to leave, after her performance.
But KK wanted to listen to other players.
So we stayed there for about two hours and listened to 13 players.
While they played the guitar, I recorded.
Because I had nothing. Of course I didn’t know them.
That night, I edited the movies it and created KK’s movie and
uploaded to YouTube.
I only made DVD for those playeres whose families didn’t take videos.
The teacher must have given them to the students.