Question 115·Easy·Form, Structure, and Sense
In the coastal city of Porto, a network of narrow streets and historic buildings ____ visitors eager to experience Portugal’s maritime heritage.
Which choice completes the text so that it conforms to the conventions of Standard English?
For subject-verb agreement questions, first strip away prepositional phrases like "of narrow streets and historic buildings" to find the core subject (here, "network"). Decide if that subject is singular or plural, then match it with the correct verb form and tense based on the sentence’s time frame (general facts usually take simple present). Compare each answer choice against both number (singular/plural) and tense, eliminating any that don’t fit one or both.
Hints
Find the true subject
Ignore the words in the prepositional phrase starting with "of" for a moment. What single noun remains as the main subject of the sentence?
Check singular vs. plural
Ask yourself: Is that main noun something that you would usually think of as one thing or more than one thing? Your verb form must match that choice.
Consider the time frame
Is the sentence describing a general fact about Porto (something that is generally true), or a completed action in the past? Choose a verb tense that fits that time frame.
Step-by-step Explanation
Identify the verb and its subject
Look at the blank: it must be filled by a verb that shows what the subject does. The full subject of the sentence is "a network of narrow streets and historic buildings." The word "of" starts a prepositional phrase, so the core subject is the noun "network," which is singular.
Decide on singular vs. plural verb form
Because the core subject "network" is singular, the verb must also be singular. In the present tense, singular verbs usually end with -s (for example, "she walks," "the city attracts"). Plural verbs usually do not end in -s (for example, "they walk," "the cities attract").
Determine the correct tense from context
The sentence describes a general, timeless characteristic of Porto: what its network of streets and buildings does for visitors in general. For general statements like this, we use the simple present tense, not past tense and not present perfect ("have" + past participle).
Choose the verb form that fits both number and tense
We need a singular, simple present verb form to match the singular subject "network" and to express a general fact. Among the choices, "guides" is the singular simple present form and correctly completes the sentence.