Organization of Ideas
Find the paragraph's job first
Every revision question starts the same way: read the whole paragraph and state its main idea in your own words before you look at the choices. A topic sentence announces that idea, and every supporting sentence must explain, illustrate, or prove it. A sentence can be factually true and still be wrong for the paragraph if it does not serve the main idea. That is the most common trap in 'which sentence should be deleted' items.
Order and connection
Coherence depends on sequence and signposts. Chronological order suits narrative and process, order of importance suits argument, and cause-and-effect order suits explanation. Transition words must match the actual relationship between ideas: 'however' signals contrast, 'therefore' signals a result, 'for example' signals illustration. A frequent trap is a transition that mislabels a relationship, so the sentence belongs but the connector is lying about its job.
Placement questions
When asked where a sentence should go, look for the words it depends on. Pronouns and repeated nouns must follow their antecedents, and a sentence usually belongs after the idea it develops and before the idea that builds on it. Concluding sentences should echo the main idea without introducing new evidence or a new topic.
Rule of thumb
State the paragraph's point in one sentence. Then point at each sentence and ask, 'How does this support that point?' If you cannot answer in a few words, that sentence is a candidate for deletion or relocation.