下列不属于软磁材料特点的是:_________________。
A. 易磁化
B. 退磁快
C. 磁滞回线宽
D. 磁滞回线窄
I __________________an earlier train, So I __________________here for two hours.
A. take; am
B. took; am
C. take; have been
D. took; have been
I’ve seen some karting races on TV but I’ve never _________.
A. have a try
B. have a go
C. had a go
D. try
测量以下那颗星的地平高度就可作为观测地点的近似地理纬度?
A. 天狼星
B. 北极星
C. 金星
D. 月球