张阿姨给孩子买衣服,有红、黄、白三种颜色,但结果总是至少有两个孩子的颜色一样,她至少有( )孩子.
阅读理解,判断对错,正确的写“正确”,错误的写“错误”
My name is Tom. My birthday is June 2nd. The weather is sunny and hot. It's my favourite season. On my birthday, I usually have a birthday party. Sometimes we have a picnic. Tomorrow is my birthday. I am cleaning the room now. My mom is making a birthday cake for me.
①取一定量该固体粉末于试管中,加适量水,得到无色澄清碱性的溶液.
②取少量步骤①所得的溶液于试管中,加足量硝酸酸化后,再加入少量AgNO3溶液,产生白色沉淀.
请根据实验现象分析:混合物中一定含有____;一定不含有____;可能含有____.
“择其善者而从之,其不善者而改之。”这句话说明( )①要克服盲目从众的心理 ②要有明确的是非观念,能够独立思考③要维护社会公平 ④要信守承诺