A sheep ________ on this kind of special grass usually grows faster than _____ on ordinary.
He made another wonderful discovery,_____ of great importance to science.
When the poor old lady tried to ______ the cup on the shelf to have a drink, she ______.
Maria has written two novels, both of _____ have been made into television series.
Mary is ill today. If she ______ ill, she _______ absent from school.
Mary had promised to give me a ticket for tomorrow. She failed, ______.