Recall the analogies in questions 3 and 4 above: shakespeare: plays : : screen: computer : : in 2-5 sentences, explain whether each item in the two analogies (shakespeare/plays, screen/computer) is concrete or abstract. how do you know?

These so called word analogies or verbal analogies are available in lot of different types. In the examples given below the first one  Shakespeare/plays, it is classified as performer and action analogy. The second one screen/computer corresponds to the type of an object and part of the whole Analogy.

Both are concrete analogies. Concrete analogies tend to be used to illustrate abstract concepts.

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.