A modifier question tests whether an opening describing phrase points to the right noun. Read the phrase and ask who or what it describes; for a phrase about how something was made, ask what was made. The main noun right after the comma must be what the phrase describes. Find that main noun, looking past any owner's name, then read to the period. Naming the right thing later in a choice doesn't fix a wrong noun at the start.
Hints
- Hint 1
Look at the phrase before the blank. What does it say about how something was built?
- Hint 2
Use the words after the blank as a clue. What does it do, and what kind of thing could do that?
- Hint 3
Check the main noun right after the comma, rather than only the first word of a longer group. Does that main noun name what was built?
Step-by-step
Match the opening phrase to its main noun
Step 1Spot the opening description
Built from software modules tells us how something was made without naming that thing. What does the sentence need after the comma? An opening describing phrase, called a modifier, describes the main noun right after its comma, so that noun must name the thing that was built.
- Step 2
Name the thing being described
What was built, and what does it do? The modules process data on both seasonal inflow patterns and hour-to-hour electricity demand, and the sentence says it recommends when a hydropower operator should conserve reservoir water. These details point to a software tool that uses data to guide decisions. The hydropower operator receives the advice rather than being the thing built from modules.
- Step 3
Test the main nouns
Apply Built from software modules to each choice's main noun. The start two related priorities makes priorities the thing built, and the hydropower operator makes the user of the tool the thing built. In the purpose of, the main noun is purpose, not the model named later. The purpose is what the model is for, not the model itself, so mentioning the model inside that longer noun group doesn't make the model the noun the opening describes.
- Step 4
Check the owner and the main noun
In the regional utility's resource-planning model, the main noun is model; the regional utility's tells us whose model it is. The opening Built from software modules now describes that model, and it recommends refers back to the same model. The colon follows a complete sentence and introduces the model's advice about conserving water and increasing low-carbon generation. Choice B.