单项选择题

Theunderlinedsentenceinthelastparagraphprobablymeansthat______.
A.theproblemisnotapproachedstepbystep
B.theresearchessofarhavefaultsinthemselves
C.theproblemistoodifficultforresearcherstodetect
D.researchinthisareaisnotenoughtomakegeneralizedpatterns

A.
A.theproblemisnotapproachedstepbystep
B.theresearchessofarhavefaultsinthemselves
C.theproblemistoodifficultforresearcherstodetect
D.researchinthisareaisnotenoughtomakegeneralizedpatterns
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