If _______ unsolved, this may lead to more serious problems.
—I would never ever come to this restaurant again. The food is terrible! —________________.
—David has made great progress recently. —_______, and __________.
The number of people invited _________ fifty, but a number of them __________ absent for different reasons.
Someone called me up in the middle of the night, but they hung up_________I could answer the phone.
The WTO can’t live up to its name _________ it doesn’t include a country that is home to one fifth of mankind.