题目

 —Have you ever explored the British Museum? —Yes. When I was in London, I ________ it twice. A. had visited            B. would visit           C. visited                 D. have visited 答案：C如果甲数是a，比乙数的2倍少b，那么表示乙数的式子是（　　）A．2a+bB．2a-bC．a+b2