若你生活在北宋末年，你可以看到哪些技术的运用 （    ）
①用活字印刷术印刷麻纸书籍   ②利用火药开山采矿   ③运用指南针航海   ④翻阅《授时历》计算日期

根据短文内容, 选择正确答案。

      Bats are the only “flying animals” in the world. They can't see very well. We often hear “as blind as a bat”. Yet they have no trouble flying on the darkest nights and finding their ways round. How can bats fly and see at night? They fly by radar(雷达).

      The bat's radar system(系统) works the same way as the radar in ships and planes. As a bat flies through the air, it makes a sound. If the sound hits things, it will come back and the bat’s ears will receive the message. In this way the bat is able to know where the things are. Bats go out for food at night. In the daytime they hang in some dark places. Some people think bats are bad animals. In fact they are useful animals.

选出下面成语使用错误的一项（    ）