在下列实数中，无理数是（　　）

如图：在△ABC中，AD是∠BAC的平分线，DE⊥AC于E，DF⊥AB于F，且FB=CE，则下列结论：：①DE=DF，②AE=AF，③BD=CD，④AD⊥BC．其中正确的结论是____．（填序号）

如图是人类某种遗传病的系谱图，Ⅱ₄是患者。排除多基因遗传病和染色体异常遗传病且不考虑基因突变的情况下，下列相关叙述有错误的是(    )

我们常常说的三年内战又叫第三次国内革命战争，那么内战开始的标志是国民党进攻（    ）

读一读，回答下列问题。
    Betty is very happy because she moves to her new home today. Her new home is very big and nice. It has three bedrooms. The big one is for her parents. The small one is for her brother Paul and the middle one is for her. Betty likes pink，so her bedroom is a pink room. The walls are pink. The curtains(窗帘)are pink. The bed and wardrobe(衣柜)are pink, too. Every day, Betty does her homework in her bedroom. Betty's father likes the new home, too. He likes the study because it's quiet. He can read in it. Betty's mum likes the kitchen. It is big and clean. She can cook nice food for the family. Paul likes the new home because the living room is so big and he can play games with his friends there.