(1)那些動詞后用原形動詞(infinitive without “to” )?
動詞后用原形動詞(infinitive without “to”)的有：
behold(12 世紀前用字，現(xiàn)代英文中極少用)，bid, feel, have, hear, let, make,
observe, perceive, see, watch, 另help后，可用to(英式英文)或不用to(美式英文)。
(2) play piano or play the piano？
彈奏或演奏樂噐，在樂噐之前要加定冠詞 the.
例如：He plays the organ in the church on Sundays.
She practices playing the violin almost every day.
(3)sometime vs. some time vs. sometimes
1. sometime: (過去的)某一時候；來日，改天
例如：I stayed in Taichung sometime last summer. 去年夏天某個時候，我待過臺中。
例如：I’ll go to Taichung to see you sometime next summer. 明年夏天某個時候，我
去臺中看你。
2. some time: 一段時間
例如：I stayed in Taichung (for) some time last summer. 去年夏天，我在臺中待過一段時間。
3. sometimes: 有時候
例如：Sometimes I go to Taichung for business. 有時候我去臺中出差。
(4)What a beautiful girl she is! vs. How beautiful a girl she is!
兩句都是驚嘆句，意思一樣，只是一用what, 一用how開始。如用what開始，則是 what a + 形容詞；如用how開始，則是how + 形容詞。
(5) I have just received a letter from my father
vs.
I just received a letter from my father
Just當剛才或方才（a moment ago）解釋時，英式英文用現(xiàn)在完成式，美式英文用簡單過去式。但just now（剛才）不論英式英文或美式英文均用簡單過去式。
例如：I received a letter from him just now.
(6) go to bed vs. go to sleep
go to bed 是就寢，go to sleep是入睡。我們可以確知自己幾時、幾分、甚致幾秒就寢，但卻無法確知自己幾時、幾分入睡。
例如：I always go to bed at 11 o’clock every night.
I don’t know when I went to sleep last night.
(7) ago vs. before
ago 是現(xiàn)在的過去多久時間before是過去的過去多久時間。
例如：He transferred to another university two years ago. transferred是過去式，是從說這句話時推算two years ago.
He told me that he had transferred to another university two years before.
told是過去式，had transferred是過去里的過去(past in the past)，因為它發(fā)生在過去式told之前，此時時態(tài)要用過去完成式，并用before, 否則他可能是兩年前或三年前告訴(told)我，加兩年或三年便是四年或五年了，而非兩年前。
此外，在直接句改為間直接句時，如直接句中有 ago，間直接句中要改為 before.
例如：Direct: Joy said, “I read that novel a year ago.”
Indirect: Joy said that she had read that novel a year before.
(8) The house which I went into is big.
vs.
The house into which I went is big.
The house which I went into is big. 是一般的英文。
The house into which I went is big. 如將into 放在which之前，即是該句的加強句。
此外亦可寫為The house that I went into is big.( 非正式英文。)
但如寫為The house into that I went is big.因為that 作關(guān)系代名詞用時，前面不得用前置詞。
(9)
形容詞子句中關(guān)代用 that 時與名詞子句如何區(qū)分？
1. The fact THAT she has inner grace(內(nèi)在美) is more important.
2. The fact THAT we must recognize is the lack of respect for the old.
3. I like the student THAT is gentle and respectful.(彬彬有禮)
第一句中THAT是連接詞，連接The fact與 she has inner grace.
THAT she has inner grace是名詞子句，作the fact的同位語，而且
she has inner grace可獨立成句。
在名詞子句中的THAT也稱為名詞子句的符號 (the sign of noun clause)。
第二句中THAT是關(guān)系代名詞，作為recognize的受詞，亦可用which代替它成為：
That fact WHICH we must recognize is the lack of respect for the old.
第三句中THAT也是關(guān)系代名詞，作為is gentle and respectful的主詞
第二、三句中we must recognize(無受詞)及is gentle and respectful(無主詞)
均無法獨立成句。
區(qū)分兩者的方法是：
a. THAT在附屬子句中是否作主詞或受詞，如果是，則是形容詞子句。
b. THAT在附屬子句中如果既非主詞，又非受詞，只有連接功能時，則是名詞子句。
摘譯自拙著p.134, Practical English Grammar and Rhetoric(實用英文文法與修辭. 第九版第五刷)
(10)
on Taiwan vs. in Taiwan
在島上的「在」用 on英國人用 on但亦可用 in. Taiwan 是一個島，所以用on 或in.
例如：He lives in (on ) Taiwan.
通常身在臺灣的人說： “We live in Taiwan.”
身不在臺灣的人說： “They live on Taiwan.”
(11)always vs. never
always & never 均為頻率副詞 (adverbs of frequency)，我們用百分比來細分它們的差異：
always—100% all of the time
usually—80% most of the time
often—50% much of the time
sometimes—30% some of the time
seldom—almost never
never—not at any time
(12)everyday 是形容詞
例如：everyday life, everyday dialogue, everyday clothes(便服), etc.
She wears everyday clothes every day after retirement.
He practices everyday English dialogue with his brother every day.
every day 是副詞詞組或名詞詞組在句子中作副詞用
例如：He goes to the park for a walk every day.( 副詞詞組)
Generally speaking, every day is a fine day in summer. (名詞詞組)
(13)eat one’s words vs. break one’s words
eat one’s words 失言，為說錯話而道歉，承認自己的錯誤
例如：He ate his words at the meeting twice.
break one’s words 食言
例如：He never breaks his words. 他從不食言，他從不爽約.
(14) aim at vs. aim to
aim at + ving 企圖，意欲，瞄準目標
例如：Henry aimed at passing the Joint College Entrance Examination.
aim + to企圖，意欲，瞄準目標
例如：Henry aimed to pass the Joint College Entrance Examination.
(15)名詞food一字是可數(shù)或不可數(shù)名詞？
A. food 指食物通稱時，是不可數(shù)名詞，例如：food and drink(食物與飲料)。但指食物種類時是可數(shù)名詞，例如：
1. Milk is a valuable food.
2. She eats the plainest of foods. (她吃最清淡的食物)
3. My students eat too many sweet foods, like cakes and pastry.
其它如health foods(各種保健食品)，baby foods (各種嬰兒食品)等。
動詞后用原形動詞(infinitive without “to”)的有：
behold(12 世紀前用字，現(xiàn)代英文中極少用)，bid, feel, have, hear, let, make,
observe, perceive, see, watch, 另help后，可用to(英式英文)或不用to(美式英文)。
(2) play piano or play the piano？
彈奏或演奏樂噐，在樂噐之前要加定冠詞 the.
例如：He plays the organ in the church on Sundays.
She practices playing the violin almost every day.
(3)sometime vs. some time vs. sometimes
1. sometime: (過去的)某一時候；來日，改天
例如：I stayed in Taichung sometime last summer. 去年夏天某個時候，我待過臺中。
例如：I’ll go to Taichung to see you sometime next summer. 明年夏天某個時候，我
去臺中看你。
2. some time: 一段時間
例如：I stayed in Taichung (for) some time last summer. 去年夏天，我在臺中待過一段時間。
3. sometimes: 有時候
例如：Sometimes I go to Taichung for business. 有時候我去臺中出差。
(4)What a beautiful girl she is! vs. How beautiful a girl she is!
兩句都是驚嘆句，意思一樣，只是一用what, 一用how開始。如用what開始，則是 what a + 形容詞；如用how開始，則是how + 形容詞。
(5) I have just received a letter from my father
vs.
I just received a letter from my father
Just當剛才或方才（a moment ago）解釋時，英式英文用現(xiàn)在完成式，美式英文用簡單過去式。但just now（剛才）不論英式英文或美式英文均用簡單過去式。
例如：I received a letter from him just now.
(6) go to bed vs. go to sleep
go to bed 是就寢，go to sleep是入睡。我們可以確知自己幾時、幾分、甚致幾秒就寢，但卻無法確知自己幾時、幾分入睡。
例如：I always go to bed at 11 o’clock every night.
I don’t know when I went to sleep last night.
(7) ago vs. before
ago 是現(xiàn)在的過去多久時間before是過去的過去多久時間。
例如：He transferred to another university two years ago. transferred是過去式，是從說這句話時推算two years ago.
He told me that he had transferred to another university two years before.
told是過去式，had transferred是過去里的過去(past in the past)，因為它發(fā)生在過去式told之前，此時時態(tài)要用過去完成式，并用before, 否則他可能是兩年前或三年前告訴(told)我，加兩年或三年便是四年或五年了，而非兩年前。
此外，在直接句改為間直接句時，如直接句中有 ago，間直接句中要改為 before.
例如：Direct: Joy said, “I read that novel a year ago.”
Indirect: Joy said that she had read that novel a year before.
(8) The house which I went into is big.
vs.
The house into which I went is big.
The house which I went into is big. 是一般的英文。
The house into which I went is big. 如將into 放在which之前，即是該句的加強句。
此外亦可寫為The house that I went into is big.( 非正式英文。)
但如寫為The house into that I went is big.因為that 作關(guān)系代名詞用時，前面不得用前置詞。
(9)
形容詞子句中關(guān)代用 that 時與名詞子句如何區(qū)分？
1. The fact THAT she has inner grace(內(nèi)在美) is more important.
2. The fact THAT we must recognize is the lack of respect for the old.
3. I like the student THAT is gentle and respectful.(彬彬有禮)
第一句中THAT是連接詞，連接The fact與 she has inner grace.
THAT she has inner grace是名詞子句，作the fact的同位語，而且
she has inner grace可獨立成句。
在名詞子句中的THAT也稱為名詞子句的符號 (the sign of noun clause)。
第二句中THAT是關(guān)系代名詞，作為recognize的受詞，亦可用which代替它成為：
That fact WHICH we must recognize is the lack of respect for the old.
第三句中THAT也是關(guān)系代名詞，作為is gentle and respectful的主詞
第二、三句中we must recognize(無受詞)及is gentle and respectful(無主詞)
均無法獨立成句。
區(qū)分兩者的方法是：
a. THAT在附屬子句中是否作主詞或受詞，如果是，則是形容詞子句。
b. THAT在附屬子句中如果既非主詞，又非受詞，只有連接功能時，則是名詞子句。
摘譯自拙著p.134, Practical English Grammar and Rhetoric(實用英文文法與修辭. 第九版第五刷)
(10)
on Taiwan vs. in Taiwan
在島上的「在」用 on英國人用 on但亦可用 in. Taiwan 是一個島，所以用on 或in.
例如：He lives in (on ) Taiwan.
通常身在臺灣的人說： “We live in Taiwan.”
身不在臺灣的人說： “They live on Taiwan.”
(11)always vs. never
always & never 均為頻率副詞 (adverbs of frequency)，我們用百分比來細分它們的差異：
always—100% all of the time
usually—80% most of the time
often—50% much of the time
sometimes—30% some of the time
seldom—almost never
never—not at any time
(12)everyday 是形容詞
例如：everyday life, everyday dialogue, everyday clothes(便服), etc.
She wears everyday clothes every day after retirement.
He practices everyday English dialogue with his brother every day.
every day 是副詞詞組或名詞詞組在句子中作副詞用
例如：He goes to the park for a walk every day.( 副詞詞組)
Generally speaking, every day is a fine day in summer. (名詞詞組)
(13)eat one’s words vs. break one’s words
eat one’s words 失言，為說錯話而道歉，承認自己的錯誤
例如：He ate his words at the meeting twice.
break one’s words 食言
例如：He never breaks his words. 他從不食言，他從不爽約.
(14) aim at vs. aim to
aim at + ving 企圖，意欲，瞄準目標
例如：Henry aimed at passing the Joint College Entrance Examination.
aim + to企圖，意欲，瞄準目標
例如：Henry aimed to pass the Joint College Entrance Examination.
(15)名詞food一字是可數(shù)或不可數(shù)名詞？
A. food 指食物通稱時，是不可數(shù)名詞，例如：food and drink(食物與飲料)。但指食物種類時是可數(shù)名詞，例如：
1. Milk is a valuable food.
2. She eats the plainest of foods. (她吃最清淡的食物)
3. My students eat too many sweet foods, like cakes and pastry.
其它如health foods(各種保健食品)，baby foods (各種嬰兒食品)等。