Hi, the
OG presents crocodile's child in SC. It means you would see not more than 10 major rules (except the idiomatic ones) in their around 400 problems in two books:
OG 10 &
OG 11. So practicing them and understanding each SC problem should provide you more than 80% success in SC within short time, assuming you have average level success now. Be alert of the following rules:
(1) Subject-verb agreement: Try to identify the subject in single word. Very often, test makers make the subject long by adding successive
prepositions at its right or inserting adjective clause (which starts with who, which, that etc.). Read the sentence excluding the prepositional or clause parts to find the single subject quickly. Then see whether the sub matches with its verb.
(2) Pronoun usage: GMAT's favorite! Check whether who, which, that, when used as
relative pronouns, have proper referents. The referents must be clear, hence must be very close to the subject, most of the cases at immediate right.
(3) Tense: Keep tense consistent in the sentence. Be careful about past indefinite, perfect etc.
(4) Comparison: Be careful about positive, comparative and superlative degree. as...as, more than..., less...than, more x than y etc. are typical constructions.
(5) Modifier: Understand dangling and other modifiers.
(6) Parallelism: Keep similar parts grammatically similar. To run, walk, and to swim (not swimming) are good exercises.
(7) Practice common frequently encountered idiomatic expressions.Luck!