The traditional view is ______ we sleep because our brain is “programmed” to make us do so.
20.You have to have a good preparation for the exam__________ you can do well in it.
--I'm calling to say goodbye. I'm flying home tomorrow. --_________.
It's_________you do it fight now_________makes a difference.
They _________to see you off at the airport, but they got there too late.
-- Excuse me, Sir. You_________take your camera into the museum. -- Sorry, I didn't know and I promise you I_________.