【判断题】A1 A2 A3 A4 Smith M 30 40 Zhang F 70 75 Wu F 70 75 M 80 80 Li F 55 75 Ting F 88 75 The above table is a relation, notice that some values may be empty in the first attribute A1. In this case, the attr...
【简答题】Translating the following paragraph: Potatoes stored below about 10C(50F) continue to build up high levels of sugar, while the same potatoes stored above 10C do not. This property is used to help the ...