题目

基因型为AaBb、aaBb的两个体杂交（两对基因满足自由组合定律），后代中纯合体占总数的                                                       A．1/4         B．3/4          C．1/2        D．2/3 答案：A下列单句均有一处错误，指出并改正 That is the only thing which was given to me by my best friend. ________