I have been __ the computer since this morning.

I have been __ the computer since this morning.

• A. On
• B. At
• C. In
• D. With

Answer: (A)

The idea being tested is which preposition we pair with a device to express ongoing activity. When you’re using a computer, the natural expression is “on the computer” to show you’re actively engaged with it, not just physically located at it. That fits with the present perfect continuous “have been … since this morning,” signaling a continuing activity from the morning until now. Saying “at the computer” focuses more on where you are rather than the act of using the machine, which slightly shifts the emphasis. “In the computer” isn’t used for this sense, and “with the computer” would imply a different nuance, not the direct action of using it. So the sentence sounds natural as: I have been on the computer since this morning.

The idea being tested is which preposition we pair with a device to express ongoing activity. When you’re using a computer, the natural expression is “on the computer” to show you’re actively engaged with it, not just physically located at it. That fits with the present perfect continuous “have been … since this morning,” signaling a continuing activity from the morning until now. Saying “at the computer” focuses more on where you are rather than the act of using the machine, which slightly shifts the emphasis. “In the computer” isn’t used for this sense, and “with the computer” would imply a different nuance, not the direct action of using it. So the sentence sounds natural as: I have been on the computer since this morning.