题目

—When ________ she have P.E.?—She ________ it on Tuesday. A . does；has B . does；have C . do；have D . do；has 答案：A5．下列计算，正确的是（　　）A．-a2b+2a2b=a2bB．3a-a=aC．2a3+3a2=5a5D．3a+2a=5a2