— Are you pleased with what he has done?— It couldn’t be ________. He must have put a lot of effort into his work.

It is required that passengers remain ________ when the plane is taking off or landing.

  Of the Kar’s boys, Robert is the richest; in other words, Andrew and Krist are _____.

When dealing with students, teachers are supposed to adopt _______ and caring approaches, as they are unique young individuals of different personalities. 

Since the office building is being repaired and painted, we will have ______ offices in the hotel．