I've been studying Spanish for a few months, I completed Duolingo. I'm generally good with languages, this is my fifth. I use a combination of grammar/textbooks and raw exposure. I understand that grammar is important (I used to teach Japanese at a college) but I don't go that deeply into it unless I have to.

I'm attempting to pass the CLEP and I have been making more errors on the practice drills than I thought I would. The answer key is something like this :

____________ a él, no a ella.

(A) Le parecen

(B) Se lo enseñaron

(C) Se negaron

(D) Los vieron

"Choice (A) is incorrect because “parecerse a” (to resemble) requires a reflexive pronoun, but we are given the third person singular indirect object pronoun. In (C), we find the reflexive form of “negar,” which is used in the idiomatic expression “negarse a” infinitive (to refuse to). The “a” in our sentence, however, is not followed by an infinitive, but rather by a prepositional pronoun, “él.” In (D), we have used the third person plural masculine form of the direct object pronoun. Since we are referring to “él” (him), for this to be correct, we would have to use the masculine singular form of that pronoun, “lo.” (B) is correct. It says, “Se lo enseñaron” (They showed or taught it to him). Observe the two object pronouns at the beginning of this answer. Remember that if we have two third person object pronouns (the first indirect, the second direct), the first of these automatically changes to “se.” In our sentence, then, the “Se” would actually stand for the word “le.” English speakers might question why the indirect object pronoun appears here since later in the sentence we find the prepositional phrase “a él,” which means “to him.” Nevertheless, the redundant use of the indirect object pronoun is typical of Spanish style, even though there may be a prepositional phrase later in the sentence which explicitly states the same idea."

That is seriously too technical for me. I've never gone that deep into grammar in any of the languages I speak, and I work as a translator!

Do I really need that level of in-depth grammatical knowledge to pass the tests? I usually absorb grammar by osmosis and exposure.