He or she is just totally fixated on learning everything about some single topic.
Men, by contrast, seem better able to focus intensely on single topics.
A normal university course might then be completed in three or four weeks of focused effort on a single topic.
No single topic is more than four pages long, so you can read many before your coffee gets cold.
What this means is about six minutes on a single topic.
Today, the single topic of conversation among the poor is hunger.
Each issue is devoted to a single topic of interest.
Often a single topic can consume an entire day or more.
Not since 9/11 have I seen any country's news media outlets so preoccupied with a single topic.
I had six minutes to write as much as possible about a single topic.