Question 194·Medium·Boundaries
Dr. Maria Telkes, often called the "Sun Queen," devoted her career to solar energy research. Her work on the Dover House, a solar-heated home built in Massachusetts in 1948, demonstrated the practicality of solar thermal storage _____ inspired later generations of engineers.
Which choice completes the text so that it conforms to the conventions of Standard English?
For punctuation questions with words like "which," "who," or "that" after the blank, first decide whether the clause is independent or dependent and whether it is essential or extra information. If it is a nonessential relative clause (extra information) that cannot stand alone, it usually needs a comma, not a semicolon or colon. Quickly test semicolons and colons by asking: "Is there a complete sentence on both sides for a semicolon?" and "Do I truly need to formally introduce an explanation or list for a colon?" If not, favor a comma when attaching a nonessential clause to a noun.
Hints
Look at the word after the blank
Focus on the word "which" that comes right after the blank. Think about what kind of clause usually begins with "which."
Check if the second part is a complete sentence
Ask yourself: Can the part starting with "which inspired later generations of engineers" stand alone as its own sentence? Your answer will affect whether a semicolon is acceptable.
Think about extra vs. necessary information
Does the clause starting with "which" restrict which solar thermal storage systems we mean, or does it just add extra information about them? The answer will help you choose the right punctuation.
Step-by-step Explanation
Identify what comes after the blank
Look at the words immediately following the blank: "which inspired later generations of engineers." This is a clause starting with the relative pronoun "which," giving extra information about something mentioned just before the blank.
Decide what kind of clause it is
A clause starting with "which" cannot stand alone as a complete sentence; it depends on a noun before it. Here, it is adding extra, nonessential information about "solar thermal storage systems" (or the work involving them), not changing which specific systems you are talking about.
Match the punctuation to the clause type
Nonessential (nonrestrictive) clauses that begin with relative pronouns like "which" are normally set off from the main sentence with a comma, not joined by a semicolon or colon and not left unpunctuated. Therefore, the correct choice is B) systems, which.