Their carelessness ______ the failure. That is to say, the failure_____ their carelessness.

High up in the mountains _____ a quiet small village, with only 20 households

Where do these books ______? — Put them back ______ they were

When the manager goes out forvacation, he always leaves his secretary ____ the factory.[ ]

though they are not doubtful at all _______ John will pass the exam, I still wonder ______ he is fully prepared.