An agreement question with several nouns tests whether you can find the verb’s true subject. Sort the forms with it and they: one thing takes a singular verb, and more than one takes a plural verb. Then ask which part of the sentence needs the blank’s verb, and find the subject within that part. Cross out phrases that describe nouns or add extra information, because a nearby noun may not be the subject.
Hints
- Hint 1
In the second sentence, find the verb that already goes with the opening words.
- Hint 2
Look at the part beginning with to which. Ask which words name what affects the laws.
- Hint 3
Around the blank, cross out the describing phrases and the extra information between commas. Can you replace the remaining subject with it or they?
Step-by-step
Find the subject inside the clause
Step 1Sort the verb forms
The choices differ in number, so start by sorting them with it and they. Which forms go with one thing? constrains, has constrained, and is constraining all fit it, so they’re singular. To fill the blank before the range of laws left in force, we need to find who or what affects that range.
- Step 2
Separate the two verbs
Which verb already goes with The extent? It has is therefore difficult later in the sentence, so the extent is what’s difficult to infer. The part starting to which is a clause, a group of words with its own subject and verb, inside the larger sentence. Because which follows to, it isn’t the subject, so the clause’s subject comes after that phrase.
- Step 3
Find the clause’s true subject
The words issued by state supreme courts describe where the decisions came from, so cross them out. Does rather than the stated preference of any one justice make the preference part of the subject? No, it adds extra information between commas, so we can remove it without changing who or what affects the laws. With those phrases out, the subject is the court decisions.
- Step 4
Match the plural subject
Replace decisions with they, and test the short form: they constrain the range of laws. Because decisions are plural, constrain is the form that matches their number. Choice A.