He was memorizing their appearance.是什么意思？

He was memorizing their appearance.

他是在记忆他们的外表.

he

pron. 他，它，一个人；n. 雄性动物；

例句
Logic had prevailed and he had abandoned the idea.
最终理智占了上风，他打消了那个念头。

was

v. 用来表示某人或某物即主语本身，用来表示某人或某物属于某一群体或有某种性质（ be的过去式 ），在，存在，不受干扰；

例句
There was a terrible sadness in her eyes...
她眼神中流露出深深的悲伤。

memorizing

v. 记住，熟记（ memorize的现在分词 ）；

例句
The man looked at them all as though he were memorizing them.
那人把他们盯着看,好象在使劲记住他们.

their

pron. 他（她，它）们的，在提及性别不详的人时，用以代替 him 或 her；

例句
Their permissiveness toward their children reflects the wild abandon of their own lives.
他们对孩子的放任折射出他们自身生活的放浪形骸。

appearance

n. 外貌，外观，出现，露面，[哲]现象；

例句
It was the president's second public appearance to date...
这是总统到那时为止的第二次公开露面。