To understand the complex situation completely requires more thought than ________ so far.

--- Do you want a lift home? --- It’s very kind of you , but I have to work late in the office . I over slept this morning because my alarm clock _________ .

With the introduction of digital equipment, a growing audience_______ back to the cinema in the past years.

—Where is your brother?   —He has gone to Beijing. He         back in three days.

--The window is dirty.----I know. It ______ for weeks.