Question 223·Easy·Boundaries
The solar rover has a limited battery _____ can operate for only about eight hours before recharging.
Which choice completes the text so that it conforms to the conventions of Standard English?
For punctuation and sentence-boundary questions, first test each side of the punctuation mark: if both sides can stand alone as complete sentences, you have independent clauses. Then recall the legal ways to join them: period, semicolon, or comma + coordinating conjunction (FANBOYS). Eliminate options that use just a comma, no punctuation, or awkward combinations like a colon plus an extra conjunction, and choose the option that cleanly and logically links the clauses.
Hints
Locate the verbs
Find the verbs on each side of the blank and decide whether each side could stand alone as a complete sentence.
Decide what kind of clauses you have
Once you know whether each side is a complete thought, ask yourself: are these two independent clauses or is one dependent on the other?
Match the punctuation to the clause types
Think about which punctuation marks correctly connect two independent clauses, and which combinations create errors like comma splices or run-on sentences.
Check how the colon and conjunction work
For any option that uses a colon or a conjunction, ask whether the part after the colon is directly explaining or illustrating the first part, and whether the conjunction is needed or makes the sentence awkward.
Step-by-step Explanation
Identify the clauses in the sentence
Read the sentence around the blank: "The solar rover has a limited battery life ______ it can operate for only about eight hours before recharging."
Split it into parts:
- Clause 1: "The solar rover has a limited battery life" (subject = "The solar rover," verb = "has").
- Clause 2: "it can operate for only about eight hours before recharging" (subject = "it," verb = "can operate").
Both parts have a subject and a verb and can stand alone as complete sentences, so they are independent clauses.
Recall how to join two independent clauses
When you have two independent clauses in one sentence, standard options are:
- Period: make two separate sentences.
- Semicolon: join the clauses if they are closely related.
- Comma plus a coordinating conjunction (FANBOYS: for, and, nor, but, or, yet, so).
You cannot correctly join two independent clauses with:
- Just a comma (this is a comma splice).
- No punctuation at all (this creates a fused sentence or run-on).
Check each answer choice against the rules
Now test each punctuation option between the two independent clauses:
- "life, it": This leaves just a comma between two complete clauses, which is a comma splice (incorrect).
- "life it": This puts no punctuation between two complete clauses, creating a run-on sentence (incorrect).
- "life: and it": A colon can introduce an explanation, but it should be followed directly by the clause that explains or expands on the first. Adding "and" after a colon is not standard here; it creates an awkward and ungrammatical structure.
Only one remaining option uses punctuation that correctly links two related independent clauses.
Confirm the best punctuation choice
The only choice that correctly and smoothly joins the two independent clauses is the semicolon:
"The solar rover has a limited battery life; it can operate for only about eight hours before recharging."
So the correct answer is "life; it".