What this lesson covers
- Items in a list, pair, or comparison must share the same grammatical form
- Match gerunds with gerunds and infinitives with infinitives
- Correlative pairs (not only/but also, both/and, either/or) take the same form on each side
- Compare like with like: her writing to his writing, not her writing to him
Chapters
- 0:00One list, one form
- 0:25Matching the shape
- 0:56Worked example: hiking, swimming, and biking
- 1:38Correlatives: not only but also
- 2:14Your turn
- 2:56Three traps
- 3:28Recap
Lesson transcript
The narration of the video, word for word, under its chapter headings.
0:00One list, one form
Welcome to SAT Climb. On weekends she enjoys hiking, swimming, and to bike. Hiking, swimming, biking? Or hiking, swimming, to bike? Most students never notice the list quietly changed shape. But the digital SAT is testing one thing: every item in a list has to wear the same grammatical form. Nail that one habit, and these questions turn automatic.
0:25Matching the shape
Here's the whole method. Every item in a list, a pair, or a comparison must share one grammatical form. Two forms trip students up the most. First, the gerund, the -ing shape: hiking, running, being. Second, the infinitive, the to plus verb shape: to hike, to run, to be. Line the items up on one rail. The first item sets the form, and every slot after it has to match. Don't pick by sound. Find the form the list already uses, then match it.
0:56Worked example: hiking, swimming, and biking
Back to our sentence. On weekends she enjoys hiking, swimming, and to bike. Find the form the list set. Hiking is a gerund, the -ing shape. Swimming is a gerund too. Two items, one form. Then comes to bike, an infinitive. That breaks the rail: the same short list is suddenly wearing two different shapes, and the SAT wants them identical. The minimal fix is to match what's already there. Two gerunds are set, so the third becomes a gerund: biking. Hiking, swimming, and biking. One list, one shape, done.
1:38Correlatives: not only but also
Parallelism also controls correlative pairs, the two-part connectors: not only, but also; both, and; either, or. Whatever structure follows the first half has to be mirrored after the second. Look at this. The policy was praised not only by teachers but also parents applauded it. After not only, we get by teachers, a simple prepositional phrase. But after but also, we get a whole clause, parents applauded it. The two sides don't match. Mirror it instead: not only by teachers but also by parents. Two matching by phrases. Same shape on both halves.
2:14Your turn
Your turn. The coach reminded the team to arrive early, to stretch fully, and blank. Look at what the list already set. To arrive. To stretch. Both are infinitives, the to plus verb shape. So the missing item has to be an infinitive too. Option A, hydrating often, is a gerund, the wrong shape, so it breaks the pattern. Option B, to hydrate often, is an infinitive that matches the two before it. The answer is B. Two infinitives set the form, so the third is an infinitive.
2:56Three traps
Three traps. One, mixing a gerund and an infinitive in the same list. If two items are -ing, the third is -ing too. Two, correlative sides that don't mirror. After not only comes a by phrase, so after but also, use a by phrase, not a whole new clause. Three, comparisons of unlike things. Her writing is stronger than her brother compares writing to a person. Make it her brother's, so you compare writing to writing. Every trap is the same idea: match the form.
3:28Recap
Parallel structure, solved. Find the form the list already uses, then make every item match it. Correlative pairs mirror on both halves, and comparisons compare like with like. Master this and you'll catch points most students hand away. Start practicing free at S.A.T. climb dot com. Keep climbing.
Read the written version: the Form, Structure, and Sense strategy guide, then try 25 hard Form, Structure, and Sense questions with full explanations. Both are free, no account needed.