对交流电机的定子铁心，在电磁方面要求它具有较高的（）性能，较低的（）。
参考答案：导磁；铁耗
While Helen _____ along the river after supper, she ____ a wallet lying on the roadside.
A. was walking; was finding B. walked; found
B. walked; was finding D. was walking; found
西晋陆机的《文赋》把文章分为（）文体。
A、五种
B、八种
C、九种
D、十种
