OG详解-OG2 数学2 Q25

Choice C is correct. Since angles B and  E each have the same measure and angles C and F each have the same measure, triangles ABC and  DEF are  similar, where side BC corresponds to side EF. To determine whether two similar triangles are congruent, it is sufficient to determine whether one pair of corresponding sides are congruent. Therefore, to determine whether triangles ABC  and DEF  are congruent, it is sufficient to determine whether sides  BC and EF have equal length. Thus, knowing the lengths of  BC and  EF is sufficient to determine whether triangle ABC  is congruent to triangle  DEF .
Choice A is incorrect and may result from conceptual errors. Choice B is incorrect and may result from conceptual errors. Choice D is incorrect. The given information is sufficient to determine that triangles ABC and DEF  are similar, but not whether they are congruent.