Question 190·Easy·Boundaries
The desert environment appears barren at first _____ a closer look reveals a surprisingly diverse ecosystem thriving beneath the sand.
Which choice completes the text so that it conforms to the conventions of Standard English?
For SAT Standard English "boundaries" questions, first test whether the words before and after the punctuation form complete sentences. If both sides are independent clauses, eliminate options that use just a comma (comma splice) or that combine a semicolon with a coordinating conjunction. Then, match the logical relationship (contrast, addition, cause/effect) to a correct pattern: comma + FANBOYS for simple links, or semicolon / semicolon + conjunctive adverb + comma for more formal connections.
Hints
Check if each side of the blank is a complete sentence
Read the words before the blank as one unit and the words after the blank as another unit. Does each part have its own subject and verb, forming a complete thought?
Figure out the relationship between the ideas
Ask yourself: Are the two ideas similar, contrasting, or cause-and-effect? What is the writer trying to show about the desert?
Match the punctuation to the sentence type
Once you know you are joining two complete sentences that contrast, think about which punctuation patterns correctly join independent clauses and which ones create comma splices or misuse semicolons.
Step-by-step Explanation
Identify the clauses on each side of the blank
Look at the text before and after the blank and decide if each side is a complete sentence (an independent clause).
- Before the blank: "The desert environment appears barren at first" — this has a subject ("The desert environment") and a verb ("appears"), so it is a complete sentence.
- After the blank: "a closer look reveals a surprisingly diverse ecosystem thriving beneath the sand" — this also has a subject ("a closer look") and a verb ("reveals"), so it is another complete sentence.
Since both sides are complete sentences, the blank must correctly join two independent clauses.
Decide the relationship between the two clauses
Now think about how the ideas are related.
- First idea: The desert seems barren at first.
- Second idea: A closer look shows a surprisingly diverse ecosystem.
These ideas contrast with each other: what appears empty actually hides a lot of life. So we need a connection that shows contrast and correctly joins two independent clauses.
Recall the correct ways to join two independent clauses
There are a few standard, correct ways to join two complete sentences:
- A comma + a coordinating conjunction (FANBOYS: for, and, nor, but, or, yet, so):
- Example: "..., but ..."
- A semicolon by itself:
- Example: "...; ..."
- A semicolon + a conjunctive adverb + a comma (such as however, therefore, moreover):
- Example: "...; however, ..."
Watch for incorrect patterns like:
- A comma alone between two sentences (comma splice).
- A semicolon plus a coordinating conjunction (like "; but"), which is redundant and wrong.
- A conjunctive adverb like "however" used between two sentences without correct punctuation around it.
Compare each answer choice to the rules
Use the rules from Step 3 to check each option:
- "glance, but": Comma + "but" (a coordinating conjunction) correctly joins two independent clauses and shows contrast.
- "glance; however": This starts a conjunctive adverb after a semicolon but is missing the comma that should follow "however" at the start of the second clause.
- "glance; but": A semicolon should not be followed by a coordinating conjunction like "but"; we either use a semicolon alone or a comma + "but".
- "glance, however,": This leaves two independent clauses separated only by commas, which is a comma splice.
The only choice that correctly and clearly joins the two contrasting independent clauses according to Standard English conventions is "glance, but".