隐极式发电机的定子绕组所感应的电势的波形随时间而变化、完全决定于电机里气隙磁通密度的空间分布状况。
参考答案：对
用am, is, are填空。
1. What _____ those? _____ they birds?
2. He _____ my friend. _____ your friend a boy or a girl?
3. This _____ his ruler. Where ______ my ruler?
4. I _____ in Class Three. ______ you in Class Three,too?
5.Those ______ their apples. Where ______ his apples?
