Which of the following is a common mistake that people make when writing summaries

The common mistake is that they write down the whole passage in present Tense.

  A common mistake that people often make are missing key components of what was written. Things such as the main context and other pieces that defined the writing in the first place, too short of a summary can often be overlooked at as if the person who wrote the summary skimmed through the subject. I think it's important to try and include everything you can in a summary so that the person reading can validate what they read.