如图所示，电磁起重机的吸盘（主要部分是电磁铁）吸起铁器静止在空中（吸盘下表面水平）．下列与此相关的说法正确的是（　　）

根据课文《歌唱二小放牛郎》内容填空。

本课是一首歌词，记叙了抗日小英雄____为了掩护八路军后方____和几千个____，把____引进埋伏圈，自己英勇牺牲的事迹。

阅读下列短文，从每题所给的四个选项（A、B、C、D）中选出最佳选项。

Mr. Lewis was a dance teacher. He was a nice man and always had a lot of students. One year he moved to a new town, and was soon teaching many students in the dance school there, but he decided to move again to a big city. He would have more work there.

    When one of his students heard that he was going to leave, she said to him, "The new teacher won't be as good as you are." Mr. Lewis was happy when he heard this, but he said, "Oh no. I'm sure he'll be as good as I am ---- or even better." The student said, "No. Five teachers have come and gone while I've been here, and each new one was worse than the last."