The School Tests and the Critical Mom's Kids

When I pick up my daughter and ask, "so how was school?" she says, "We had the math test today."  And she looks either worried or thrilled, but has gotten very good at not showing her hand. 
"So how did it go?"
"And by the way we had to do our timetable in English for English class, too."
"Yes, and that's 'schedule' in American, by the way."
"I know, Mommy! So I read 'math or mathematics' and she said, 'Yes, that's mawths."
"She's correcting you?"
"Mawths!"
"Moths are funny little insects that congregate around light bulbs.  How was the math test you took?"
"Well, Mommy . . . ." and I cannot for the life of me tell whether the look is one of suppressed glee or dejection.  We're walking out the school door and she wants to go the long way, but I'm carrying her seven-ton schoolbag and it's raining, so I insist that we proceed as quickly as possible to the nearest tram stop.
"If we go my way, I'll tell you right now.  Otherwise, I'll tell you at home."
"So, okay, tell me at home."  She looks murderous and is good as her word.  The minute we're in the door and the schoolbag lands with a resounding thump, the muscles in my shoulder buzzing, she says, "Well, Mommy, only one person in the class got nothing wrong," (with a very convincing look of despair.)  "There were ten ones, five twos, three fours, and about six fives.  Only one person got nothing wrong. . .  AND THAT WAS ME!" With a tooth-sparkling grin and a high five.  Wow.  So we're very happy.  Then her brother comes home, and all is straightforward:
"Guess what Mom I gotta one on the Chemistry test!" 
"You could do pre-Med!" I say, with my usual over-enthusiasm.  The poor kid's only twelve.
"Nah, I don't wanna be a doctor.  What else can I do with Chemistry?"
"Oh, research, or---"
SLAM!
He's behind his door immersed in Minecraft by the end of the sentence.  Later, he's correcting his English exam.  The teacher is not a native speaker.  I am, and my husband might as well be, having lived in Southern California for seven sunny years.  Our son had written, "For how long did you live in Paris?" The teacher had marked that wrong.  My husband didn't see anything wrong with it and neither did I.  This may be the very same teacher who pronounced the word "lettuce" as "letooose." We all sat around eating pumpkin soup, listening to the rain, missing the eldest child, who is having fantastic time in Southern China, and wondering what unexpected pronunciations of common words our kids might hear from their English teachers, none of whom seems to have come across this handy guide: