I wonder if you know it ___ .
The number of people in the party _____fifty, but a number of them ____ absent for different reasons.
He asked us ________ we saw the lost cat or not.
After the exam, my teacher told me that failure ____ the mother of success.
In order to stop his wife from attending the party, he took away the key to their car _____.
— I am taking the college entrance examination next week. — ___ _!