In this task, you will be shown an incorrect English sentence. You need to generate a corrected form of the input sentence.

Ex Input:
This casts doubt in the reading passage 's assertion that fluoride prevents dental cavities .

Ex Output:
This casts doubt on the book passage 's assertion that fluoride prevents dental cavities .

Ex Input:
this economics system is the best .

Ex Output:
This economics system is the best .

Ex Input:
Also , the professor indicates prescribed fire should be carful when we use prescribed fire solution .

Ex Output:
Also , the professor indicates that we should be careful when we use the prescribed fire solution .