Which of the following passages is written for expert pianists?
my fingers softly pressed the black and white keys, and i marveled at the soft tones emanating from the piano.
i always knew i should be practicing scales and arpeggios to enhance my fingering skills, but i always preferred to spend my time on a little rhapsody in blue--extra fortissimo!
my first piano was a beautiful, glossy upright cabinet, and i would polish the smooth cherry wood until i could see my reflection in it.
my teacher, miss minchen, could always tell when i stretched the truth about how many hours i was practicing each week.

The passage that is written for expert pianists is I always knew I should be practicing scales and arpeggios to enhance my fingering skills, but I always preferred to spend my time on a little Rhapsody in Blue--extra fortissimo!

All pianists are expected to practice scales and arpeggios. This is what allows a pianist to become familiar with the piano keys which is crucial for a pianist. So in this passage, it is clear that he wanted to play Rhapsody in Blue instead of practicing scales and arpeggios.

quite an interesting way to teach topic sentences, because the answer to this question is the best definition of a topic sentence that one can present, it is as if answering the questions taught you how to do it, this is some real teaching, it is terribly well-done.

the topic sentence in this paragraph is:

topic sentences writers stay on track and keep a paragraph from becoming an aimless collection of sentences about an idea.

which incidentally tells you what a topic sentence should be.