TASK DEFINITION: In this task, you will be shown an incorrect English sentence. You need to generate a corrected form of the input sentence.
PROBLEM: Video is convenient , but , if teachers concern about students , so using texetbooks gives good ability for students .

SOLUTION: Video is convenient , but if teachers are concerned about students , using textbooks can give students good abilities .

PROBLEM: In extreme cases , some even gain weight because of this .

SOLUTION: In extreme cases , some even gain weight because of this .

PROBLEM: These kind of fish ca n't live so long in water that contain salt .

SOLUTION:
These kind of fish ca n't live so long in water that contain salt .