SAT OwlQuestion bank / Form, Structure, and Sense
When the Kessling Marsh reserve was established in 1994, only a dozen pairs of herons nested there. Since then, careful management of water levels ______ the colony to grow to more than three hundred pairs, making it one of the largest in the region.
Which choice completes the text so that it conforms to the conventions of Standard English?
had allowed
allows
will allow
has allowed
Show answer and explanation
Answer: D
"Since then" describes a span of time that began in the past (1994) and continues to the present. That calls for the present perfect, "has allowed." The singular subject "management" also matches "has."
Choice A is a perfect tense too, but "had allowed" places the action before another past event, while "since then" runs up to the present.
Why the other choices are wrong
- A. "Had allowed" places the action before some other past event, but "since then" runs up to the present.
- B. "Allows" is simple present and doesn't fit "since then," which needs an action continuing from the past to now.
- C. "Will allow" is future tense, but the colony has already grown.
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