After a week, my cousin had not _____ able to think of any good slogans.

After a week, my cousin had not _____ able to think of any good slogans.

• A. Did
• B. Was
• C. Been
• D. Are

Answer: (C)

The sentence tests using the past perfect form with be able to to express inability up to a past point. After a week indicates we’re talking about a time further back in the past, up to that moment when the statement is made. To say he could not think of good slogans up to then, we use had not been able to. The structure is had not been (past participle of be) plus able to + verb, here think. Using Been is necessary because the verb to be takes the form been in the perfect construction, and it correctly links with able to. The other options don’t fit because they don’t combine with the perfect tense and the be-phrase in the required way: did is the past simple of do, which wouldn’t follow had not; was is the past tense of be but doesn’t pair with been in this construction; are is present tense and inappropriate for a past reference.

The sentence tests using the past perfect form with be able to to express inability up to a past point. After a week indicates we’re talking about a time further back in the past, up to that moment when the statement is made. To say he could not think of good slogans up to then, we use had not been able to. The structure is had not been (past participle of be) plus able to + verb, here think. Using Been is necessary because the verb to be takes the form been in the perfect construction, and it correctly links with able to.

The other options don’t fit because they don’t combine with the perfect tense and the be-phrase in the required way: did is the past simple of do, which wouldn’t follow had not; was is the past tense of be but doesn’t pair with been in this construction; are is present tense and inappropriate for a past reference.