读课文《翠鸟》回答。

翠鸟蹬开苇秆，像箭一样飞过去，叼起小鱼，贴着水面往远处飞走了。

这句话中把____比作了____，体现了翠鸟____。

(A)

    China Youth says that more and more girl students have entered colleges to study in the recent few years. As we know, once the number of boys was larger than that of girls, and boys did much better than girls in our country for a long time. Now, things have changed a lot.

    In recent years, the proportion of girl students is growing fast. In 1998, about 39.7% of college students were girls. In 2000, it was 41.07% and in 2001, the number was 42.14%.

    There are several reasons for this.

    Firstly, there is little difference between boys and girls in their intelligence(智力). That's to say, girls are as clever as boys. And boys have more interests than girls, so they may not always do well in their study.

    Secondly, girls are more careful than boys. They work harder at school and they do better in all exams. Another reason is that with the development of society, people pay more and more attention to girls' education.

长方体ABCD—A₁B₁CD中，$AB=2\sqrt{3},AD=2,A{A}_1=\sqrt{6}$，则点D₁到直线AC的距离是(     )