是
A:1
B:2
C:1
D:图(2)的结论:DF+BE=AF;图(3)的结论:BE﹣DF=AF;图(2)的证明:延长CD到点G,使DG=BE,连接AG,需证△ABE≌△ADG,∵CB∥AD,∴∠AEB=∠EAD,∵∠BAE=∠B′AE,∴∠B′AE=∠DAG,∴∠GAF=∠DAE,∴∠AGD=∠GAF,∴GF=AF,∴BE+DF=AF;图(3)的证明:在BC上取点M,使BM=DF,连接AM,需证△ABM≌△ADF,∵∠BAM=∠FAD,AF=AM∵△ABE≌A′BE∴∠BAE=∠EAB′,∴∠MAE=∠DAE,∵AD∥BE,∴∠AEM=∠DAB,∴∠MAE=∠AEM,∴ME=MA=AF,∴BE﹣DF=AF.