1 He is heavier than other boy in his class
2 Of the two hats，he chose the least expensive one
3 The population of Canada is smaller than of Africa
4 I‘m more taller than any other classmate in our class
5 She has three times as much books as i
6 China is larger than any other country in Africa
7 This is a most beautiful park .I have never seen a best one before.
8 He said that his son worked there happy every day
注明原因 谢谢 ！
1.he is heavier than other boys in his class 他比班上其他男孩都高（注意boys必须用复数）
2.一般现在时，三单肯定句chose变形choses
3.that that但指代人口。
4.classmate要变复数，any other说的是
5.tall的比较级直接加er，不必多加more
6.中国不属于非洲，所以不能写any other
7.This is the most beautiful park.I have never seen a better one.8.He said that his son worked happily there every day.副词修饰动词。