要构筑拒毒心理防线，我们需要做到（）
A.正确把握好奇心
B.抵制不良诱惑
C.养成良好的健康心理
D.以上表述均正确
参考答案：D
His writing is so neat that it’s easy for the teacher to make out ______ he is trying to express.
A．what is it that
B．that it is what
C．that is it what
D．what it is that
PC机操作系统是通过（）来识别文件类型的。
A、文件扩展名
B、文件头
C、文件名
D、文件
