Slip-ups (Temporal and Temporary)

Today, your favourite and ever popular Junior Graphic is beginning a new column with the title SLIP-UPS.
The essence of the new column is to draw attention to the many common errors people make as they use English in their everyday discourses --- conversations, writings, correspondence, examinations, etc.
The ultimate aim is to make all of us identify such common errors and avoid them.
As pupils and students who have English Language examinations to write in the nearest future, we cannot afford to make the mistakes many people take for granted because we need to pass our examinations well to be able to climb the academic ladder to the very top.
To make the column interactive and very relevant to you, my dear readers, I  want you to bring to my attention any such slip-ups you come across, so that your fellow pupils and students elsewhere can also become aware of them.
Your interaction with the column could be in the form:
Why do we say or write:
I