) A, BB and C contain amylase in saliva, which can catalyze starch hydrolysis. Amylase can catalyze starch hydrolysis, but not sucrose hydrolysis. (3) Dropping iodine solution into boiling water bath with Garfield reagent can catalyze starch hydrolysis into reducing sugar, but not sucrose. Starch turns blue when exposed to iodine, and maltose and sucrose do not turn blue when exposed to iodine, so iodine solution can only be used to detect whether starch is hydrolyzed, but not whether sucrose is hydrolyzed. A is compared with B. A is a blank control. Through comparison, it can be concluded that amylase in saliva can catalyze starch hydrolysis. The purpose of comparison between B and C is to draw the conclusion of enzyme specificity. The product of starch hydrolysis is maltose (reducing sugar), and sucrose is non-reducing sugar. If it can be hydrolyzed, the product is glucose (reducing sugar). Therefore, the iodine solution used to detect the experimental results can be changed into Phyllin reagent, and the experimental purpose can be achieved.