题目

The $11 billion self-help industry is built on the idea that you should turn negative thoughts like I never do anything right into positive ones like I can succeed. But was positive thinking advocate(倡导者) Norman Vincent Peale right? Is there power in positive thinking?Researchers in Canada just published a study in the journal Psychological Science that says trying to get people to think more positively can actually have the opposite effect: it can simply highlight how unhappy they are.The study's authors, Joanne Wood and John Lee of the University of Waterloo and Elaine Perunovi下列实验基本操作正确的是（　　）A．稀释浓硫酸时，将水沿器壁缓慢注入浓硫酸中B．过滤时，漏斗里液体的液面要高于滤纸的边缘C．胶头滴管的管口直接伸入试管里滴加液体，以免外溅D．实验室取用液体药品做实验时，如没有说明用量，一般取1～2 mL