Miss Li asked a question, but it was ________ that nobody could answer it. [ ]
Who’s that boy reading in the garden? Is it David?— It ____________ be David. I saw him in the classroom just now．
Mom, when can I go out to play football?—Finish your homework first, or I ________let you go out.
_______Today is a fine day,and I will go on a trip to the countryside for the fresh air. _______Have fun_, and_______yesterday.
How long have you ______ this book ?