题目

用某种酶处理转化因子后，R型细菌不再转化成S型细菌，这种酶是      A．蛋白酶                            B．分解多糖荚膜的酶            C．DNA酶                             D．纤维素酶   答案：C How ________ you feel? ________ you cold, my boy? [　　] A．are, Are B．are, Do C．do, Are D．do, Do