Something will have to be done about the air pollution, _______ ?
At times, worrying is a normal, ________ response to a difficult event or situation --- a loved one being injured in an accident, for example.
This cake is very sweet. You _____ a lot of sugar in it.
He paid for a seat, when he ______ have entered free.
— The woman biologist stayed in Africa studying wild animals for 13 years before she returned. — Oh, dear ! She ______ a lot of difficulties !
Helen ______ go on the trip with us, but she isn’t quite sure yet.