--- You may refuse my invitation , but you must explain why . --- Oh, I must , _____ ?
John is ill and has been __________ by Tom in our team in tomorrow's football match.
She concentrated her energies __________ her test.
My deskmate and Tom are similar __________ each other __________ character.
The company,__________ in 2003, is one of the most famous compa-nies.
—How often do you eat out? —__________,but usually once a week.