Forming questions with be able to involves inverting the subject and the correct form of the verb to be for the relevant tense.

Here’s a detailed explanation along with examples for different tenses:


Present Tense
Explanation: Use the present tense form of to be (am, is, are) before the subject and follow it with able to.

Examples
1. Singular Subject
Statement: She is able to speak French.
Question: Is she able to speak French?

2. Plural Subject
Statement: They are able to finish the work.
Question: Are they able to finish the work?

Past Tense
Explanation: Use the past tense form of to be (was, were) before the subject and follow it with able to.

Examples
1. Singular Subject
Statement: He was able to solve the problem.
Question: Was he able to solve the problem?

2. Plural Subject
Statement: We were able to attend the concert.
Question: Were we able to attend the concert?

Future Tense
Explanation: Use will before the subject, followed by be able to.

Examples
1. Singular Subject
Statement: She will be able to come tomorrow.
Question: Will she be able to come tomorrow?

2. Plural Subject
Statement: They will be able to complete the project.
Question: Will they be able to complete the project?

Present Perfect Tense
Explanation: Use have or has before the subject, followed by been able to.

Examples
1. Singular Subject
Statement: He has been able to improve his skills.
Question: Has he been able to improve his skills?

2. Plural Subject
Statement: They have been able to reach an agreement.
Question: Have they been able to reach an agreement?

Past Perfect Tense
Explanation: Use had before the subject, followed by been able to.

Examples
1. Singular Subject
Statement: She had been able to finish the task.
Question: Had she been able to finish the task?

2. Plural Subject
Statement: We had been able to solve the issue.
Question: Had we been able to solve the issue?

Modal Verbs with Be Able To
Explanation: Use the modal verb (like might, may, should) before the subject, followed by be able to.

Examples
1. Singular Subject
Statement: He might be able to join us.
Question: Might he be able to join us?

2. Plural Subject
Statement: They should be able to complete the work.
Question: Should they be able to complete the work?

Negative Questions with Be Able To
Explanation: To form negative questions, add not after the subject or use contractions.

Examples
1. Singular Subject
Statement: She is not able to come.
Question: Is she not able to come? or
Isn't she able to come?

2. Plural Subject
Statement: They were not able to fix the car.
Question: Were they not able to fix the car? or Weren't they able to fix the car?