答案：D

题目分析：考查连系动词：sound为系动词，后跟形容词，sound pretty good为系表结构。而sound like后加名词，如That sounds like a good idea,（那听起来是个好主意。）因为这里省略了主语that，所以是sounds。选D。

点评：连系动词：用于连接主语和表语，说明主语的状态、性质特征或身份等。常见的连系动词分类：表示状态的be, seem, appear等。表示感觉的look, sound, feel, smell, taste等由变化而来。表示状态变化的become, get, grow, turn, fall等。其它：stand, keep, prove, remain等。注意：系动词后不用副词，用形容词，系动词不用被动语态。She sings beautifully. Her song sounds beautiful