Breakdown of Peter lernt viel, Tom ist dagegen das völlige Gegenteil.
sein
to be
lernen
to learn
viel
much / a lot
Peter
Peter
Questions & Answers about Peter lernt viel, Tom ist dagegen das völlige Gegenteil.
Doesn't a "da-" word like dagegen normally mean "against it"?
You are right that dagegen often literally means "against it" (like in Ich bin dagegen - I am against it). However, it is also frequently used as a linking adverb to express a contrast, translating to "on the other hand" or "by contrast".
Could I put dagegen at the beginning of the second clause?
Yes, you can! Because dagegen is an adverb, placing it at the beginning of the clause takes up position 1, meaning the verb must immediately follow in position 2: ... dagegen ist Tom das völlige Gegenteil. Putting it after the verb, as in this sentence, is just as natural and shifts the spoken emphasis slightly onto Tom.
Why does völlig have an -e at the end in das völlige Gegenteil?
Gegenteil is a neuter noun (das Gegenteil). Because it follows the definite article das, the adjective völlig (complete/total) takes the weak ending -e for the nominative case.
Can I use studiert instead of lernt if Peter is studying hard for a test?
No, you must use lernen for general studying, reviewing for a test, doing homework, or acquiring a skill. In German, studieren is exclusively used to mean being enrolled at a university or majoring in a specific academic subject.