In the fragments of the text: “they may lose the desire to master whatever task you are asking them to do” (lines 12-13) and “then you have to do more than just present lessons in the app” (lines 18-19), the verb forms in bold express the ideas, respectively, of 
In the sentence of the text: “However, if you want people to continue using the app, and use it frequently and often, then you have to do more than just present lessons in the app” (lines 17-19), the connector However can be replaced, without any change in meaning, by 
Based on the meanings of the words in Text I, 
The sentence, in Text I, in which the boldfaced expression introduces an idea of addition is 
In Text I, the expression “turn down” in “I couldn’t turn down the great starting salary and a chance to live in New Orleans” (lines 12-14) could be replaced, without change in meaning, by 
In "slight adjustments to related definitions may be required."(lines 29-30), the fragment “may be required” can be substituted by
Check the only item in which the boldfaced item introduces a contrast.
Mark the only option in which the two words ARE NOT synonymous.
In line 72, the author juxtaposes the words “Dubbing (drubbing?)”. This play on words corresponds to the meanings in
The connectors “Likewise” (line 44) and “unlike” (line 83) express ideas that are similar to those denoted by
