_______ your valuable help
_______ your valuable help, we couldn't have finished the experiment ahead of time.
A.If it were not for
B.Had it not been for
C.Were it not for
D.If it has not been for
A.If it were not for
B.Had it not been for
C.Were it not for
D.If it has not been for
参考答案:B
参考解析:正在整理中,欢迎在文下评论区提供答案解析,谢谢!