4.When Zhou Kai's mother saw him heading towards the front door without a jacket on, she eyed him anxiously.

　　妈妈看到周凯没穿夹克就向前门走去，担心地盯着他。

　　(1)see sb. doing sth. 看见某人正在干某事。（强调动作的进行）

　　see sb. do sth. 看见某人做了某事。(强调动作的全过程)

　　[举例]I saw him drawing the picture when I passed by his room.

　　当我从他房间经过时我看见他正在画画。

　　I saw him break the window yesterday.

　　我昨天见他把窗户打破了。

　　[拓展]有类似用法的动词还有：hear, notice, watch ,feel , listen to等。

　　[经典考题] The______ boy was last seen _______neat the East Lake. （上海2000）

　　A. missing; playing B. missing; play C. missed; played D. missed; to play

　　[点拨]答案为A miss作"丢失"讲，为不及物动词，用missing作定语；句中的last强调动作(play)发生的时间。

　　(2)句中的head 和eye均作为动词，是由其名词转化而来，意思分别为"朝方向前进"和"注视，观看"。短语 head towards /for 意思为"朝......前进"；注意eye的其它形式：eyeing/eying. eyed, eyed。

　　[举例]The ship was heading for Cuba.

　　船正开往古巴。

　　 We headed south towards the capital.

　　我们朝南向首都进发。

　　 He couldn't help eyeing the cake hungrily..

　　 他饥不可耐地盯着蛋糕。

　　5."No, I won't . I'll be fine ,"said Zhou Kai, as he opened the door.

　　当周凯开门时，他说我不会感冒的。

　　as作连词，引导时间状语从句，意思为"当......时候"，强调主句谓语动作与从句谓语动作的同时性。

　　[举例]As he grew older, he got more interested in science.

　　随着年龄的增长，他对科学的兴趣与日俱增。

[辨析]as , when与while