—How was your holiday? —It couldn’t have been   ．I just stayed in the hotel because it was raining most of the time．

It is a fact that _________ differences between countries may cause misunderstandings in communication.

It wouldn’t be ________ for us to attend a formal wedding with the sports clothes.

She is _______ at her boyfriend. 

 After two years’ research, we now have a ____ better understanding of the disease.