用情态动词+have done填空We __________ __________ __________ the problem in a more reasonable fashion. (本来可以解决)
The companies are working together to create ____ they hope will be the best means of transport in the 21st century.
A good story does not necessarily have to have a happy ending , but the readers must not be left ______.
Washington, a state in the United States , was named _____ one of the greatest American presidents.
The English spoken in the United States is only slightly different from ____ spoken in England.
The question of whether English will continue changing in the future is easy _______.