Perfect tenses revision

John and Sarah ______ three international conferences about AI this year.

• has attended

• have attended

• had attended

• have been attending

Marta ______ for her language certification exam since September.

• has been preparing

• have been preparing

• had prepared

• will have been preparing

By the time Lisa arrived at the airport, the plane ______.

• has already left

• have already left

• had already left

• had been leaving

By the time the conference starts, Sophia ______ her research paper.

• will complete

• will have completed

• has completed

• has been completing

The students have (a)   working on their group project for over a week.

Emma (a)   won several awards for her research on renewable energy.

By the time the lecture started, William (a)   finished reading the assigned chapter.

By next summer, Rachel (a)   have visited all the major museums in Europe.

Anna ______ two new apps to improve productivity this year.

• will have developed

• had developed

• have developed

• has developed

What does this sentence mean? 'Jake has installed the latest software update on his laptop.'

• Jake finished the update recently.

• Jake is still installing the update.

• Jake will install the update later.

• Jake has started installing but hasn't finished yet.