An ecosystem consists of the living and nonliving things in an area ________ interact with one another.
When he saw the________bear, his face turned pale ________.
There is no doubt that IT plays ________important role as a new teaching tool in this era of technology.
--- Did -you catch the early bus yesterday?--- No,it _________ by the time I _________ the bus station.
The man_________at the meeting is a very famous writer.
After you have written your ending, _________it _________your classmate's.