Teacher: You are given a passage. You need to construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) its answer is the whole paragraph. Avoid creating questions that can be answered correctly without actually understanding the paragraph.
Teacher: Now, understand the problem? If you are still confused, see the following example:
Optical mice use an LED and a camera to rapidly
capture images of the surface beneath the mouse.
The infomation from the camera is analyzed by a
DSP (Digital Signal Processor) and used to detect
imperfections in the underlying surface and
determine motion. Some materials, such as glass,
mirrors or other very shiny, uniform surfaces
interfere with the ability of the DSP to
accurately analyze the surface beneath the mouse.

Since glass is transparent and very uniform, the
mouse is unable to pick up enough imperfections in
the underlying surface to determine motion.
Mirrored surfaces are also a problem, since they
constantly reflect back the same image, causing
the DSP not to recognize motion properly. When the
system is unable to see surface changes associated
with movement, the mouse will not work properly.
Solution: why doesn't an optical mouse work on a glass
table?
Reason: The passage talks about the glass and mirror surfaces beneath the optical mice and how the mouse is unable to pick up enough imperfections in the underlying surface to determine motion. The last line of the passage explains why the mouse will not work properly on these surfaces. Thus it is a positive example.

Now, solve this instance: The difference is the level of commitment. "Dating" connotes a casual thing, not necessarily exclusive. When a person says "I'm dating Bill" instead of "Bill is my boyfriend", you can probably guess the relationship is relatively new and no commitment has been made.
When you've decided you're in a relationship, you'll probably start referring to one another as boyfriend/girlfriend. You'll introduce each other to your close friends and family. You'll likely spend a LOT of time together, and may take it for granted that you'll see each other certain nights and weekends. Depending on your lifestyle, you may agree to make your relationship exclusive and stop seeing other people.
If you're uncomfortable discussing taking things to "the next level" you're probably just dating, and not quite ready for a relationship.
Student:
What is the difference between dating and in a relationship?