动名词是非限定动词的一种形式，由动词原形+ing构成。它既有动词的特征，又有名词的特征，故称。动名词也有时态和语态的变化，如表所示（以及物动词write为例），不及物动词没有语态的变化。
时态/语态 主动 被动
一般式 writing being written
完成式 having written having been written
1. 动名词作主语、宾语和表语
1）作主语。例如：
Fighting broke out between the South and the North. 南方与北方开战了。
2）作宾语
a. 有些动词可以用动名词作宾语。例如：
admit 承认 appreciate 感激 avoid 避免 complete完成 consider认为 delay 耽误
deny 否认 detest 讨厌 endure 忍受 enjoy 喜欢 escape 逃脱 fancy 想象
finish 完成 imagine 想象 mind 介意 miss 想念 postpone推迟 practice 训练
recall 回忆 resent 讨厌 resume 继续 resist 抵抗 risk 冒险 suggest 建议
face 面对 include 包括 stand 忍受 understand 理解 forgive 宽恕 keep 继续例如：Would you mind turning down your radio a little, please? 你把收音机音量调小一点，好吗
The squirrel was lucky that it just missed being caught. 这松鼠幸运得很，刚逃避了被逮住的厄运。
b. 有些结构后面可以用动名词作宾语或其他成分。例如：
admit to, prefer…to, be used to, lead to, devote oneself to, object to;
stick to, no good, no use, be fond of, look forward to, be proud of;
be busy, can't help, be tired of, be capable of, be afraid of, think of ;
burst out, keep on, insist on, count on, set about...
put off be good at take up give up be successful in
3）作表语，对主语说明、解释。例如：
Her job is washing, cleaning and taking care of the children. 她的工作是洗刷、清扫和照顾孩子。
比较：She is washing, cleaning and taking care of the children.
4）作定语，一般表示所修饰名词事物的用途。例如：
a writing desk=a desk for writing 写字台
a swimming pool=a pool swimming 游泳池
有些动名词作定语，与所修饰的名词关系比较复杂。例如：
boiling point=a temperature point at which something begins to boil 沸点a walking tractor=a tractor which a driver can operate while he or she is walking behind it 手扶拖拉机
2. worth 的用法
worth, worthy, worthwhile都是形容词，意为"值得"。
1) worth： be worth + n. 当名词为金钱时，表示"…… 值得……"
常见的有It ’s worth while to do./ It ’s worth（someone’s）while doing
be worth doing sth. "……某事值得被做"
The question is not worth discussing again and again. 这问题不值得反复讨论。
2) worthy：be worthy of +n. 当名词为抽象名词时表示"……值得……"
be worthy to be done "某事值得被做"
The question is not worthy to be discussed again and again.
3) worthwhile：be worthwhile to do sth "值得做某事"
It is worthwhile to ask him to join the club.值得邀请他加入俱乐部。
典型例题
It is not ____ to discuss the question again and again.
A. worth B. worthy C. worthwhile D. worth while
答案C. 由worth的用法可知，此句只适合词组be worthwhile to do sth.。选C。