Step 1: Note the situation.
A student can explain a concept in words, but cannot use it in a real situation. We must decide what this tells us about the student's learning.
Step 2: Recall how learning grows in stages.
Learning is not just one jump. It builds up in steps, from knowing facts, to understanding them, to applying them, and later to analysing and creating. Each step is deeper than the one before.
Step 3: Find where this student stands.
The student can explain the idea, so the understanding step is done. But the next step, application, is the act of using the idea in real life. The student fails right here.
Step 4: Decide what a missing step means.
If a learner stops at understanding and cannot apply, the higher steps are still empty. So the learning has not finished its full journey. It is only part way through.
Step 5: Reject the wrong options.
We cannot say learning fully occurred or that the topic is mastered, because mastery needs application too. Saying teaching is unnecessary makes no sense, since the student still needs help to reach the application stage.
Step 6: State the conclusion.
Because the student cannot yet use the concept, the learning is still not whole.
\[ \boxed{\text{Learning is incomplete}} \]