During the middle of the story
It just means extremely good or wonderful.
The sum of neutrons would be 55. (: I hope this helps. because if you minus the mass number by the atomic number which is always equivalent to the number of protons, you get the amount of neutrons. The amount of protons and neutrons always add up to the mass number.
For the first red, you don't need an article before "relationship".
When you're saying "type of [word]", do not put any article before that word.
Example: "a type of device"
Not too sure about the "your back" parts. It could be your teacher does not like repition.
Also not too sure about "did". He probably wanted you to use the word "felt" instead of "did feel"
The first word of the last paragraph should be "in" not "at".
The red commas definitely do not need to be there.
Don't know why he marked "time to" and "to" red.
