“跳槽”、“打破铁饭碗”、“人才招聘会”、“上岗资格制度”等流行语突出反映了改革开放以来我国（    ）

阅读下列短文，从每小题的三个选项中选出最佳选项。

    It's autumn. It's cool and windy. Charlie is flying a kite in the park. His father is watching(观看).The kite is flying high(高) in the sky. They are happy. Look! The kite is not in the sky now. Where is it? Oh, it's in a tree. Charlie is sad. Charlie jumps and jumps. The tree is tall but he is short. He cannot get(拿到) the kite. Charlie's father is not very tall but he is clever(聪明的). Look, he is on a car. He can get the kite for Charlie. Charlie is happy.

若|a|是一个正数，那么下列说法正确的是（　　）