Glucose has a free aldehyde group which can be oxidized to the acidic groups. Hence, glucose is a reducing sugar. Starch and Cellulose are polysaccharides.

They are comprised of multiple units of glucose linked together. The glucose in starch and cellulose does not contain a free aldehyde group and hence, starch and cellulose do not act as reducing sugars.

Similarly, sucrose is a disaccharide in which the aldehyde group of glucose is used up in forming a bond between glucose and fructose.

Hence, sucrose is also not a reducing sugar.