SAT Reading & Writing: Hard Transitions (Drill 18)

Question 1. The crystallographer Dorothy Hodgkin worked out the three-dimensional structure of penicillin in the 1940s, reading the positions of its atoms from the faint patterns its crystals scattered across an X-ray film. The achievement alone would have secured her reputation among chemists; ______ she went on to map the far larger and more tangled structure of vitamin B12, a molecule so intricate that the calculations strained the early computers she enlisted, painstaking work that helped earn her a Nobel Prize in chemistry.

Which choice completes the text with the most logical transition?

• A) in response,
• B) by comparison,
• C) more impressively, ✓
• D) to put it briefly,

Explanation: (C) The second clause does not react to or summarize the first; it piles on a further, harder achievement -- the B12 structure after penicillin -- and ranks it higher. "More impressively" is the connector that both adds and elevates. (A) "In response" makes the B12 work a reaction to the penicillin result, but the passage presents it as a further accomplishment, not an answer. (B) "By comparison" invites a side-by-side weighing, yet the sentence is stacking a second success on the first, not measuring one against it. (D) "To put it briefly" signals a summary, while the B12 work is fresh information rather than a condensed restatement of the penicillin result.

Question 2. The sculptor Ruth Asawa wanted her hanging wire forms to seem almost weightless, as if a single shape could hold open a pocket of space without ever quite enclosing it behind a solid wall. ______ she looped one continuous strand of wire into nested, transparent volumes, so that an inner form seemed to float inside an outer one and the eye passed straight through both at once, reading solid mass and empty air together as a single woven gesture that seemed to weigh almost nothing at all.

Which choice completes the text with the most logical transition?

• A) Then again,
• B) To achieve that, ✓
• C) Long before that,
• D) As a result,

Explanation: (B) "To achieve that" ties the goal to the technique: wanting weightless forms, she looped continuous wire into nested volumes. Her aim leads directly to the means that realized it. (A) "Then again" reverses course to weigh a competing thought, but the looping method carries out her aim rather than qualifying it. (C) "Long before that" places the second clause earlier in time, yet the technique serves a goal already stated, not a prior moment. (D) "As a result" treats the looping as an effect of her wish, but a chosen method is a means toward a goal, not its automatic consequence.

Question 3. Studying how a soap film stretches itself into the smallest possible surface across a bent wire frame, the architect Frei Otto saw a rule he could borrow for buildings: nature tends to settle on shapes that span a given area with the least material. ______ he shaped tent-like roofs whose curved fabric pulled taut between slender masts and steel cables, covering wide public halls with a thin skin far lighter than any poured slab of concrete could ever have managed across the same open span.

Which choice completes the text with the most logical transition?

• A) On the contrary,
• B) In the meantime,
• C) By way of example,
• D) Building on that idea, ✓

Explanation: (D) "Building on that idea" carries the soap-film principle straight into his roofs, which embody the same least-material rule. The phrasal opener links a borrowed insight to the design that puts it to work. (A) "On the contrary" sets up a reversal, but the roofs apply the principle rather than contradicting it. (B) "In the meantime" marks a stretch of waiting, while the sentence shows a principle being acted on, not time passing between events. (C) "By way of example" would make the roofs an example of the soap-film rule, which tempts; but the passage frames Otto as extending the idea into new work -- an act of building on it, not a sample that illustrates it.

Question 4. To chart a stretch of seafloor in the days before sonar, a survey ship lowered a weighted rope over the side until it touched bottom, then noted the depth marked off at that single spot. The vessel steamed a fixed distance and dropped the line once more, repeating the slow cast mile after mile across open water; ______ the crew joined the scattered soundings into one continuous profile, tracing the rise and fall of ridges and trenches that no one had ever seen directly and that the charts had until then left blank.

Which choice completes the text with the most logical transition?

• A) until then,
• B) at last, ✓
• C) for example,
• D) regardless,

Explanation: (B) "At last" caps an ordered procedure: sound one spot, move on, repeat, and finally assemble the readings into a profile. This is the culminating step the earlier casts were building toward. (A) "Until then" points to the stretch before some later moment, but the clause reports the final step itself, the joining that the casts were building toward, not what preceded it. (C) "For example" promises an instance, yet the final clause reports the last action in a sequence, not an illustration of a claim. (D) "Regardless" dismisses the earlier steps as not mattering, while the profile depends entirely on those accumulated readings.

Question 5. The motion-detecting cells in a fly's eye can react to a flicker of light and recover quickly enough to register many separate changes within the span of a single human blink. That speed seems exotic only when it is held up against our own slower vision. ______ the human eye blends light flashing past more than a few tens of times each second into a single steady glow, a threshold low enough to make the fly's rapid flicker-fusion look genuinely extreme rather than merely quick.

Which choice completes the text with the most logical transition?

• A) Likewise,
• B) On the contrary,
• C) In any event,
• D) By comparison, ✓

Explanation: (D) "By comparison" sets the fly's speed beside the human baseline so the gap is visible: our vision fuses flicker at only tens of flashes a second, which is what makes the fly's far higher rate stand out. The connector measures one case directly against the other. (A) "Likewise" would assert a similarity, but slow human vision is the opposite of the fly's fast response, not a match for it. (B) "On the contrary" would correct or deny the prior sentence, yet the baseline supports the claim about the fly rather than refuting it. (C) "In any event" brushes the comparison aside as beside the point, while the human threshold is exactly what makes the fly's speed register.