下列关于有机化合物的叙述正确的是（        ）

    Beth is a shy girl. Any things can affect her____ . She often feels unhappy. She wants to ____  friends with her classmates, but she doesn’t know how to talk ____ them. Helen is a nice girl. She often ____ Beth jokes and makes her____ . Having Helen around her (Helen在身边), Beth doesn’t feel ____any more. She ____  Helen to be her friend, but she doesn’t know what to do. Could you give Beth some ____ ? Please call us____ 25681089. If you do that, she will ____  better.

2的相反数与0.5的绝对值的和是（　　）

分别向氢氧化钠溶液和澄清石灰水中通入CO₂，发生的反应可用下列化学方程式表示：

2NaOH+CO₂═Na₂CO₃+H₂O；Ca（OH）₂+CO₂═CaCO₃↓+H₂O

（1）对比上述反应得出的规律是两种碱溶液都能与CO₂反应，生成盐和水．

（2）要检验一种气体是否为CO₂，应选用上述两种碱溶液中的____；

（3）根据上述规律结合溶解性表，写出Ba（OH）₂溶液与CO₂反应的化学方程式____．