Acoustic monitoring systems can help park rangers detect illegal logging in remote forests. Using recordings collected by microphones throughout a reserve during the wet season, a machine-learning program _____ distinguishes chainsaws from naturally occurring sounds.
Which choice completes the text so that it conforms to the conventions of Standard English?
For a boundary question containing an interruption, first remove the interrupting words and identify the underlying sentence structure. Decide whether the conjunction joins independent clauses or verbs sharing one subject; then restore the interruption and punctuate it separately with the required paired marks.
Hints
Remove the interruption
Temporarily omit “as field tests have shown” and identify the subject of both main verbs.
Track both comma functions
Determine whether punctuation is needed before the coordinating conjunction, and separately determine how the interrupting clause should be set off.
Step-by-step Explanation
Identify the sentence core
Temporarily remove the interrupting clause. The sentence's core is “a machine-learning program filters ... and distinguishes....”
Analyze both boundaries
Because “filters” and “distinguishes” share the subject “program,” they form a compound predicate and should not be separated by punctuation before “and.” The clause “as field tests have shown” interrupts the second part of that predicate and therefore must be enclosed in commas.
Select the correctly punctuated choice
The choice that preserves the compound predicate while enclosing the interrupting clause is filters out background noise caused by storms and, as field tests have shown,.