Teacher: In this task, you will be shown an incorrect English sentence. You need to generate a corrected form of the input sentence.
Teacher: Now, understand the problem? If you are still confused, see the following example:
The car's wheel are loose.
Solution: The car's wheel is loose.
Reason: The instance of are is replaced by the word is. This makes the sentence grammatically correct.

Now, solve this instance: This is very useful for them . 
Student:
This is very useful for them . 