第一句：I made so many mistakes.
A: Oh, Mery! Don't weep all over the letters.
B: I made so many mistakes.
A: They are nicely set out.
第二句：But that's still my fault.
A: you can easily correct the spelling mistakes.
B: Thank you for saying that. But that's still my fault.
A: Do cheer up.
Oh, my fault for failing to get it.
I am awfully sorry. I didn't realize.