The old man was very ___ when the boy’s ball hit his windows.

The reading room is_______the classroom.

 In today’s fast changing and competitive world, to be able to learn faster and more effectively is not merely desirable; it is ________.

As we all know, independence is very ________ for youngsters because sooner or later they will leave their families and live alone. 

．The two brothers look so much ___ that we can’t___ one from the other．