etc. is not informal. In fact it is better than its expansion, which sounds rather awkward. It is perfectly ok to use etc. in an academic paper. Just note, however, that both of them are very sparingly and carefully used in serious writing. Try to list fully or describe the list instead.

"badly" is an adverb and explains how something was done. Ex: She was hurt badly. "bad" is an adjective and describes a noun. Ex: She is a bad driver. Since the word being modified is "feel" (a verb), the proper modifier is "badly" (an adverb). This is essentially the same as the difference ...

As well as being an adjective, fast is an adverb. We use it all the time as such: He ran fast. However, though slow is definitely an adjective, it sounds wrong when used as an adverb, because slowly is more common. He ran slow. We would always say: He ran slowly. My question is...

Slow has the adverb slowly. I tend to use fastly as the adverb for fast. However, it is underlined in most spell checkers I use, which makes me wonder about the existence of this word. Is fastly a correct word? If not, what should be used instead, and why is that different from its antonym? ...

its a bad thing. its when you feel ill from being out on a sunny day.

Is following sentence grammatically correct? The world is getting smaller and international connections tighter. What kind of construct is this? Parallel structure?

Is it grammatically incorrect to use a verb with multiple-meanings so that the meanings are used at once? I'm thinking of a line from the classic Flanders Swann song Madiera M'Dear: ...he hastened to put out the cat, the wine, his cigar and the lamps. Is there a name for this kind of struc...