17e6ec08_Proofreader_s_Marks__Meaning
[Symbol] tense [Explanation] Keep the tense of your essay consistent. If you talk about the action of the story in either present or past tense it is fine as long as you don't switch back and forth (except to indicate a change in the time frame of the story). [Meaning] 
tense shift
Proofreader's Marks
Meaning