The first textbooks ______ for teaching
问题:
The first textbooks ______ for teaching English as a foreign language came out in the 16th century.
A.having written
B.to be written
C.being written
D.written
The first textbooks ______ for teaching English as a foreign language came out in the 16th century.
A.having written
B.to be written
C.being written
D.written