You can hardly imagine what great difficulty we had _________ the task.

The number of the classes in our school is __________ than__________ of any other school in Nanjing．

_____haveyou practiced skating? —For five years.[ ]

Is David honest and organized boy?— Yes, that is why he was chosen to be the president of the Students’ Union.

Is this your earser?—No,it isn’t. It’s ________.