David knocked at the door for nearly half an hour______Mary opened it, unwilling.
Little ________ about his own safety, though he was in great danger himself.
________ to use in April, 2010, the road has solved the long-standing problem of traffic jams of this area.
People are puzzled ________ they read the book.
The soldier was of running away when the enemy attacked.
According to the air traffic rules, you should ________ off your mobile phone before boarding.