__________yourvaluablehelp,wecouldn'thavefinishedtheexperimentaheadoftime.
A.If it were not for B.Had it not been for C.Were it not for D.If it has not been for正确答案B
__________yourvaluablehelp,wecouldn'thavefinishedtheexperimentaheadoftime.
A.If it were not for B.Had it not been for C.Were it not for D.If it has not been for正确答案B