A true friend can see the pain in your eyes everyone else believes the smile on your face. A. while B. because C. before D. until 答案:A15.在试管内注入2mL某组织样液,再注入2mL刚刚配制的本尼迪特试剂,振荡试管,使溶液混合均匀,此时呈现蓝色.试管内某组织样液再经水浴加热后,组织样液颜色由蓝色变为红黄色(如图所示),则该组织样液为( )A.花生B.大豆C.鸡蛋清D.苹果