under

　　[誤] The lake is two meters under sea level.

　　[正] The lake is two meters below sea level.

　　[析] under的意思是在某物的下面，而below=lower than, 即低于。

　　[誤] Under the help of our teacher, all of us passed the exam.

　　[正] With the help of our teacher, all of us passed the exam.

　　understand

　　[誤] I think it is diffcult to make myself to understand.

　　[正] I think it is diffcult to make myself understood.

　　[析] 這句話的意思是我想讓別人理解我太難了。

　　[誤] I am understanding the lesson now.

　　[正] I understand the lesson now.

　　[析] understand一詞沒有進行時態。類似的詞還有belong, find, hear, love, like等。

　　until

　　[誤] We walked until the edge of the forest.

　　[正] We walked as far as the edge of the forest.

　　[誤] Our school bus can hold until twenty children.

　　[正] Our school bus can hold up to twenty children.

　　[析] until與till兩詞的意思一樣，但兩個詞都只能用于時間，如： Ill wait until I hear from you.

　　[誤] I waited for my mother to seven oclock, but she didnt come.

　　[正] I waited for my mother until seven oclock, but she didnt come.

　　[誤] Can you return this book until Monday

　　[正] Can you return this book by Monday

　　[析] 當我們談目前正在進行而將來某一時刻才停止的事件時用until，而用by來表達將來某一時刻會發生的動作。

　　[誤] We arrived home until it became dark.

　　[正] We didnt arrived home until it became dark.

　　[析] until用于肯定句時表示某動作直到為止，如： They worked until 5∶00 P. M. 用于否定句中時意為直到才。所以用于肯定句中要使用延續性動詞，但截止性動詞卻可以用在否定句中。

　　upstairs

　　[誤] He went to upstairs.

　　[正] He went upstairs.

　　[析] upstairs一詞可用作副詞，如： We all hurried upstairs to see what happened. 也可用作名詞，如; The upstairs of the house needs painting. 同時也可以用作形容詞，如： A house with three upstairs rooms is quite good.

　　use

　　[誤] It is no use to ask her.

　　[正] It is no use asking her.

　　[析] It is no use與There is no use后通常用動名詞，而不用不定式。

　　[誤] Ill get used to treat the students this way.

　　[正] Ill get used to treating the students this way.

　　[析] be used to與get used to后要接動名詞表示習慣于做某事。

　　[誤] I used to getting up early in the morning.

　　[正] I used to get up early in the morning.

　　[析] used to表示過去習慣的動作，其后要加動詞原形。

　　[誤] Oil was used to cooking.

　　[正] Oil was used to cook.

　　[析] 這里的句型雖然也是be used to但這里不是主動態，而是被動態，所以不能接動名詞而應接不定式。

　　[誤] We used to go to the Great Wall three times.

　　[正] We went to the Great Wall three times.

　　[析] used to只能用來表示一種習慣，而不能用來表達某事發生的次數。

　　under

　　[誤] The lake is two meters under sea level.

　　[正] The lake is two meters below sea level.

　　[析] under的意思是在某物的下面，而below=lower than, 即低于。

　　[誤] Under the help of our teacher, all of us passed the exam.

　　[正] With the help of our teacher, all of us passed the exam.

　　understand

　　[誤] I think it is diffcult to make myself to understand.

　　[正] I think it is diffcult to make myself understood.

　　[析] 這句話的意思是我想讓別人理解我太難了。

　　[誤] I am understanding the lesson now.

　　[正] I understand the lesson now.

　　[析] understand一詞沒有進行時態。類似的詞還有belong, find, hear, love, like等。

　　until

　　[誤] We walked until the edge of the forest.

　　[正] We walked as far as the edge of the forest.

　　[誤] Our school bus can hold until twenty children.

　　[正] Our school bus can hold up to twenty children.

　　[析] until與till兩詞的意思一樣，但兩個詞都只能用于時間，如： Ill wait until I hear from you.

　　[誤] I waited for my mother to seven oclock, but she didnt come.

　　[正] I waited for my mother until seven oclock, but she didnt come.

　　[誤] Can you return this book until Monday

　　[正] Can you return this book by Monday

　　[析] 當我們談目前正在進行而將來某一時刻才停止的事件時用until，而用by來表達將來某一時刻會發生的動作。

　　[誤] We arrived home until it became dark.

　　[正] We didnt arrived home until it became dark.

　　[析] until用于肯定句時表示某動作直到為止，如： They worked until 5∶00 P. M. 用于否定句中時意為直到才。所以用于肯定句中要使用延續性動詞，但截止性動詞卻可以用在否定句中。

　　upstairs

　　[誤] He went to upstairs.

　　[正] He went upstairs.

　　[析] upstairs一詞可用作副詞，如： We all hurried upstairs to see what happened. 也可用作名詞，如; The upstairs of the house needs painting. 同時也可以用作形容詞，如： A house with three upstairs rooms is quite good.

　　use

　　[誤] It is no use to ask her.

　　[正] It is no use asking her.

　　[析] It is no use與There is no use后通常用動名詞，而不用不定式。

　　[誤] Ill get used to treat the students this way.

　　[正] Ill get used to treating the students this way.

　　[析] be used to與get used to后要接動名詞表示習慣于做某事。

　　[誤] I used to getting up early in the morning.

　　[正] I used to get up early in the morning.

　　[析] used to表示過去習慣的動作，其后要加動詞原形。

　　[誤] Oil was used to cooking.

　　[正] Oil was used to cook.

　　[析] 這里的句型雖然也是be used to但這里不是主動態，而是被動態，所以不能接動名詞而應接不定式。

　　[誤] We used to go to the Great Wall three times.

　　[正] We went to the Great Wall three times.

　　[析] used to只能用來表示一種習慣，而不能用來表達某事發生的次數。