英語在什么時候用ing形式？

動詞-ing有兩種意義。
一種是：動作在某時刻正在進行，稱為動詞的現(xiàn)在分詞。
還有一種是：動詞在做非謂語的成分時，不能用原形，有時要用ing形式，稱為動名詞。有時也用to do 即動詞不定式。

一、動詞-ing形式做主語

1、現(xiàn)在分詞做主語表示事物化、抽象化的概念。強調：現(xiàn)在分詞做主語時謂語一律用單數。

Eg: Talking is an art.

Eg: Tearning English well is not easy.

2、it做形式主語的情況

It’s no good/use doing sth. 做``````是沒有用的

It’s useful/useless doing 做``````是有/沒有用的

There is no `````````doing sth.

Eg: It is no use crying after knowing the result.

Eg: It is no good playing games.

二、動詞-ing形式做表語

動詞-ing形式做表語，一般表示比較抽象的習慣性動作。

1、句子主語常是表示無生命的事物的名詞/抽象的習慣性動作。（主語和表語的位置可以互換）

Eg: My hobby is playing games.--------Playing games is my hobby.

Eg: One of his bad habits is speaking loudly. -----------Speaking loudly is one of his bad habits.

Eg: Your task is studying hard.-------------Studying hard is your task.

與現(xiàn)在進行時的區(qū)別：

He is flying.(現(xiàn)在進行時，就不能轉換成----------Flying is he)

2、表示主語的某種性質或狀態(tài)，描述主語的特征，相當于形容詞，故不能與主語互換。

系動詞：be動詞、感官動詞、get/become等。

Eg: This film is interesting.

Eg: Today’s weather is nice.

Eg: The song sounds good.

(主語一般為物：moving\ surprising\promising有希望的)

三、動詞-ing形式做賓語

1、作動詞的賓語

某些動詞后只能用動詞-ing形式作賓語，不能用不定式。

allow \ cannot help\ consider\ risk\ suggest\ forbid\ protect```(from)阻止\ admit\ advise\ allow\ avoid\ delay推遲\ enjoy\ escape逃脫\ finish\ give up\ imagine\ mind\ practise\

Eg: I tried to avoid making mistakes.

Eg: I suggest having a rest.

2、作介詞的賓語

是一些固定的短語搭配：be/ get/ become used to習慣于, look forward to, insist on, be succed in, be fond of, be interested in, be worth, devote```to, stick to, lead to and so on.

Eg: The book is worth reading.

Eg: I am used to getting up early.

四、作賓語補足語

1、動詞-ing形式可以在感官和心理狀態(tài)的動詞后面作賓語補足語，和賓語一起構成復合賓語。（表示動作的正在進行，狀態(tài)正在持續(xù)）

Eg: I watched a student picking peaches when I crossed the school.

Eg: When I came into classroom, I heard someone singing.

3、動詞-ing形式也可以用在使役動詞have\ get\ leave\ keep\set\ send等動詞后作賓語補足語。

（賓語與作賓補的現(xiàn)在分詞之間存在邏輯上的主謂關系，即賓語是現(xiàn)在分詞動作的發(fā)出者。）

Eg: Don’t have your students doing homework all the time.

五、動詞-ing形式做定語

1、表示被修飾詞的某種用途,一般放在所修飾詞的前面。

閱覽室 reading room 吸煙室 smoking room

洗衣機 washing machine 寫字臺 writing desk

3、起形容詞作用的動詞-ing作定語時，含有主動和進行的意思。

(1) 單個的分詞放在所修飾名詞的前面

Eg: I walked quietly in order not to wake the sleeping bird.

(2) 短語放在所修飾的名詞后面

Eg: I know the bird sleeping in the tree.---------I know the bird which is sleeping in the tree.

Eg: It lived in a tree facing my house.----------It lived in a tree which faced my house

動詞-ing有兩種意義。
一種是：動作在某時刻正在進行，稱為動詞的現(xiàn)在分詞。
還有一種是：動詞在做非謂語的成分時，不能用原形，有時要用ing形式，稱為動名詞。有時也用to do 即動詞不定式。

一、動詞-ing形式做主語

1、現(xiàn)在分詞做主語表示事物化、抽象化的概念。強調：現(xiàn)在分詞做主語時謂語一律用單數。

Eg: Talking is an art.

Eg: Tearning English well is not easy.

2、it做形式主語的情況

It’s no good/use doing sth. 做``````是沒有用的

It’s useful/useless doing 做``````是有/沒有用的

There is no `````````doing sth.

Eg: It is no use crying after knowing the result.

Eg: It is no good playing games.

二、動詞-ing形式做表語

動詞-ing形式做表語，一般表示比較抽象的習慣性動作。

1、句子主語常是表示無生命的事物的名詞/抽象的習慣性動作。（主語和表語的位置可以互換）

Eg: My hobby is playing games.--------Playing games is my hobby.

Eg: One of his bad habits is speaking loudly. -----------Speaking loudly is one of his bad habits.

Eg: Your task is studying hard.-------------Studying hard is your task.

與現(xiàn)在進行時的區(qū)別：

He is flying.(現(xiàn)在進行時，就不能轉換成----------Flying is he)

2、表示主語的某種性質或狀態(tài)，描述主語的特征，相當于形容詞，故不能與主語互換。

系動詞：be動詞、感官動詞、get/become等。

Eg: This film is interesting.

Eg: Today’s weather is nice.

Eg: The song sounds good.

(主語一般為物：moving\ surprising\promising有希望的)

三、動詞-ing形式做賓語

1、作動詞的賓語

某些動詞后只能用動詞-ing形式作賓語，不能用不定式。

allow \ cannot help\ consider\ risk\ suggest\ forbid\ protect```(from)阻止\ admit\ advise\ allow\ avoid\ delay推遲\ enjoy\ escape逃脫\ finish\ give up\ imagine\ mind\ practise\

Eg: I tried to avoid making mistakes.

Eg: I suggest having a rest.

2、作介詞的賓語

是一些固定的短語搭配：be/ get/ become used to習慣于, look forward to, insist on, be succed in, be fond of, be interested in, be worth, devote```to, stick to, lead to and so on.

Eg: The book is worth reading.

Eg: I am used to getting up early.

四、作賓語補足語

1、動詞-ing形式可以在感官和心理狀態(tài)的動詞后面作賓語補足語，和賓語一起構成復合賓語。（表示動作的正在進行，狀態(tài)正在持續(xù)）

Eg: I watched a student picking peaches when I crossed the school.

Eg: When I came into classroom, I heard someone singing.

3、動詞-ing形式也可以用在使役動詞have\ get\ leave\ keep\set\ send等動詞后作賓語補足語。

（賓語與作賓補的現(xiàn)在分詞之間存在邏輯上的主謂關系，即賓語是現(xiàn)在分詞動作的發(fā)出者。）

Eg: Don’t have your students doing homework all the time.

五、動詞-ing形式做定語

1、表示被修飾詞的某種用途,一般放在所修飾詞的前面。

閱覽室 reading room 吸煙室 smoking room

洗衣機 washing machine 寫字臺 writing desk

3、起形容詞作用的動詞-ing作定語時，含有主動和進行的意思。

(1) 單個的分詞放在所修飾名詞的前面

Eg: I walked quietly in order not to wake the sleeping bird.

(2) 短語放在所修飾的名詞后面

Eg: I know the bird sleeping in the tree.---------I know the bird which is sleeping in the tree.

Eg: It lived in a tree facing my house.----------It lived in a tree which faced my house.

這個份好多種，，
1可以是正在進行時態(tài)時候用，表示正在干什么
2可以用作主語后面做伴隨狀語用，但是主語必須是能發(fā)出這個動作的，，比如人可以發(fā)出好多動作，但是比如桌子，后面就不可以發(fā)出動作，故桌子后面就不可以接ing形式了
3還有可以在幾個特殊的動詞后面用，有些動詞后面必須加ing形式，有些可以加ing，也可以加to do等形式。。。
還有其他的情況吧
希望可以幫到你