这些题目错在哪里？

Question

1,I'm in the Class4 ,Grade 5.
2,Don't read in sun.
3,I'm the heavier than Mike.
4,I can see an bear in the forest.
5,I lie on the grass under's a tree.

Answer 1

1、不要那个the
2、在sun前面加the
3、不要那个the
4、把an改成a
5、I lie on the grass under the tree.

Answer 2

1,I'm in Class4 ,Grade 5.
2,Don't read in the sun.
3,I'm heavier than Mike.
4,I can see the bear in the forest.
5,I lie on the grass under a tree.

Answer 3

1,I'm in the Class4 ,Grade 5. 无 the
2：the sun
3：无the
4：a bear
5：under's ？？？？？