Historical experience can as a most important source of information.
The number of traffic accidents that _______ in developing countries _______ increasing.
--- Would you do me a favor and carry these books? --- ________.
_______ is necessary for you to lock the car when you don’t use it.
A small plane crashed into a hillside five miles east of the city, _______ all four people on board.
My breakfast mainly ________ chocolate-covered biscuits and glasses of milk.