___ the front door ___, he had to enter the room through the back door.
When I returned home ,I found the window _____and something____.
Come and see me whenever ____ .
The invention of steam engine greatly sped up the industrial revolution, which _____ a lot to the take-off of the world.
The quality of a processed food largely ______ the raw material and the way it _______.
—Why is he feeling down today? —Because the suggestion he________has been turned down.