43.Your trousers ______dirty,you must have______ washed.

43.Your trousers ______dirty,you must have______ washed.
A.is it B.are it C.are them D.is them
44.The Olympic games ______held every four ______.
A.is years B.are years C.is year D.are year
45.He is the oly one of the students who______elected.
A.are B.have C.has D.is
46.______a good enough price for this book
A.Two yuans are B.Two yuan are
C.Two yuans is D.Two yuan is
47.No bird and no beast ______in the lonely island
A.are seen B.is seen C.see D.sees
48.Every means ______prevent the water from______
A.are used to polluting B.get used to polluting
C.is used to ,polluted D.is used to ,being polluted
49.Each of the ______in the ship.
Apassenger has his own room
Bpassengers have their own room
Cpassenger have their own room
Dpassengers has his own room
50.What we need ______good textbooks.
A.is B.are C.have D.has