题目

阅读理解Being a teenager can be hard, for you have to face a lot ofdifficult problems, but a new program called Nfusion is working hard to helpteens with mental(精神的)healthneeds. Nfusion gives teenagers classes where they study or discuss sometroubling subjects. Drugs and bullying(欺凌)are just afew of the topics discussed during the class on Saturday.I had a bad attitude, said 17-year-old Titeana Davis.Davis went through the Nfusion Program last year. The teen, who once hadtrouble with her attitude towards others, says the program has changed her life.They taught me a bad attitude 一细束平行光经玻璃三棱镜折射后分解为互相分离的三束光，分别照射到相同的金属板a、b、c上，如题图所示，已知金属板b有光电子放出，则可知：（ B．板a一定放出光电子；C．板c一定不放出光电子；D．板c一定放出光电子。A．板a一定不放出光电子；