Use commas to separate words and word groups in a simple series of three or more items.
Example: My estate goes to my husband, son, daughter-in-law, and nephew.
Note: When the last comma in a series comes before and or or (after daughter-in-law in the above example), it is known as the Oxford comma. Most newspapers and magazines drop the Oxford comma in a simple series, apparently feeling it's unnecessary. However, omission of the Oxford comma can sometimes lead to misunderstandings.
Example: We had coffee, cheese and crackers and grapes.
Adding a comma after crackers makes it clear that cheese and crackers represents one dish. In cases like this, clarity demands the Oxford comma.
We had coffee, cheese and crackers, and grapes.
Fiction and nonfiction books generally prefer the Oxford comma. Writers must decide Oxford or no Oxford and not switch back and forth, except when omitting the Oxford comma could cause confusion as in the cheese and crackers example.
Hope this helped! :)
Answer:
"I've got a brilliant plan" said David excitedly
"I plan on helping students that doesn't speak English" said David. David's plan was to create a system that help exchange students to understand english better "it will be a system and all schools should use it" said David this system was a device that would translate words for the students that would be small and easy to carry. "it will of so much help while they get taught in classes " said David. David's device is going to help exchange students to do their best in school "it's going to work!" said David.
