-- What do you think of David ? -- There are some things that are not easy to , and his coldness is one .
______a nurse, she knew how to take care of a patient.
The______ look on his face suggested that he had passed the exam.
As a boy, he was_______ hard all day long.
Many things _______ impossible in the past are common today.
I rushed there in a taxi only _______ the library_______.