题目

—I'd like one kilo of apples and two kilos of bananas. How much are they?       —The ________ price is 20 yuan.         A. all         B. total        C. high            D. low 答案：BDNA分子的一条链中 =a，上述比例在其互补链和整个DNA分子中分别是（ ）A.a和2aB.a和aC. 和1D.a和1