They ___________ duty since 8 a.m. (a. had been performing b. have been performing)

They will have finished working.

You will regret this.

The kids ___________ cartoons all day. (a.has been watching b.have been watching)

Change this active sentence into passive voice: I will never forget this experience.

As of this moment, I ___________ everything you asked me to do. (a. have completed b. had completed c. will have completed)

We have been waiting for hours.

Which helping verb accompanies a present perfect tense verb?

The mother took the child to the doctor.

Which perfect verb tense describes actions that have continued up to the present time, though there is uncertainty as to whether the actions will continue?

I want to be a writer.

Change this passive sentence into active voice: Her lessons have been learned by her.

She _________ the meal for one hour. (a. had been cooking b.has been cooking)