题目

YaoMing is very famous now. However, his basketball career ________ only after many years of hard work. A. took on                           B. took off                  C. took up                 D. took out 答案：B 根据下图所示的电磁打点计时器构造图，指出各主要部件的名称：①________，②________，③________，④________，⑤________，⑥________，⑦________.