It’s not a particularly easy challenge, made worse by the fact that my non-native English speaking girlfriend just beat my score comprehensively (this wasn’t a difficult feat, however). The answers are provided, and I particularly like the method Wallace used to teach correct adverb use:
You have been entrusted to feed for your neighbor’s dog for a week while he (the neighbor) is out of town. The neighbor returns home; something has gone awry; you are questioned.
“I fed the dog.”
“Did you feed the parakeet?”
“I fed only the dog.”
“Did anyone else feed the dog?”
“Only I fed the dog.”
“Did you fondle/molest the dog?”
“I only fed the dog!” [Here Wallace’s voice cracked funnily.]
The excellent Tense Present: Democracy, English, and the Wars over Usage (David Foster Wallace) and Politics and the English Language (George Orwell) essays are mentioned in the answers section and are well worth your time if you haven’t read them before and have even a passing interest in grammar.