Hard( )he tried, he was unable to meet the deadline for the term paper.
A.正确答案Balthough
B.as
C.if
D.since
Hard( )he tried, he was unable to meet the deadline for the term paper.
Hard( )he tried, he was unable to meet the deadline for the term paper.
A.正确答案Balthough
B.as
C.if
D.since