I can not study as well as my older brother

=> My older brother studies well than me

He acted actively in a charitable program

=> he was active actor in a charitable program.

Try to recycle things or we will not save natural resources

=> Unless we don't try to recycle things, we will not save natural resources.

the last time i used that like was two year ago

=>That like hasn't been used in two years.

"i think people should plant a lot of trees in the sidewalk for the environment month ", said Mary

=> Mary suggested a lot of trees should be planted in the sidewalk for the environment month.

Chúc em học tốt !!!