英语高手进来改错 Mr Wang taught their Japanese last yearYou'd better

1.Mr Wang taught them Japanese last year.
teach sb. sth. 教某人东西 不能用代词
2.You'd better speak as much English as you can.
as many/much as 尽可能多的 English是不可数名词,所以用much 这里没有比较的意思
3.If you pay more attention to your spelling, you will make fewer mistakes.
mistakes是可数名词,这里用few来表示
little-less-least 修饰不可数N.
few-fewer-fewest 修饰可数N
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