A.preoccupied的意思是全神贯注的，心事重重的 B.concentrated是集中的，全神贯注的 C.absent-minded是心不在焉的，健忘的，出神的 D.thoughtful是深思的，体贴的，关切的
我的选择是C absent-minded 。大致的意思就是，我跟他说着话，但是他心不在焉的听着我说的话。

Don't be so absent-minded. 不要这么心不在焉.请问为什么要加be呢？去掉行么？

absent-minded 是一个复合形容词。形容词的两个基本用法：在名词前面做定语，比如：He is an absent-minded boy； 或者在系动词之后做表语，比如： He is absent-minded。

专门注意它作表语的用法：【都有系动词be 或者 be 随人称变化的形式：is 等】
肯定：He is absent-minded
否定：He isn't absent-minded
在情态动词后：You mustn't be absent-minded
祈使句（也叫命令句）：Don't be so absent-minded

absent的音标及意思？

absent: [ 'æbsənt ]

a. 缺席的
vt. 使缺席


词形变化:
副词:absently 动词过去式:absented 过去分词:absented 现在分词:absenting 第三人称单数:absents

例句与用法:
1. How many students are absent today?
今天有多少学生缺席？

2. He deliberately absented himself from the meeting.
他故意不到会.

3. Love was totally absent from his childhood.
他童年时代没受到丝毫的疼爱.

4. He gave a lame excuse for being absent.
他找了个站不住脚的理由来解释缺席的原因。

5. Why was it that he was absent?
他为什么缺席呢？

6. Many students were absent, notably the monitor.
许多学生缺席，特别是连班长也没来。

7. Please tell me the reason why (=for which) you were absent.
请告诉我你为什么缺席。

8. Professor Li is absent, I will take the lesson in the place of him.
李教授不在, 我替他上课。



英英解释:
动词absent:

1. go away or leave
同义词：remove

形容词absent:

1. not in a specified place physically or mentally

2. lost in thought; showing preoccupation
同义词：absentminded, abstracted, scatty