i am in hong kong

1. 這是甚麼文法

I am in Hong Kong. 我 (現正) 身在香港

句子結構： S + LV + predicate adverb
例句：I am home.

"in Hong Kong" is a prepositional phrase functions as predicate adverb telling the position 位置 of the subject.
Unlike adjunctive adverb, "predicate adverb" is obligatory 強制性的，不能省略。

I am in love. 我 (現正) 戀愛了

句子結構： S + LV + predicate adjective
例句：I am ill.

"in love" is a prepositional phrase functions as predicate adjective modifying the subject to tell its state or condition 狀態或情況. In grammar, it is also called "subject complement" (S+LV+SC).

那 in + noun 就是形容詞?
No, it depends on the meaning of the preposition "in". In most cases, it is adverb, except for:
(i) "in" = wearing something
例 She is all in black.
(ii) "in" = showing state or condition
例 She is in danger.
The house is in good repair.

2. I am loving you 同 I am a good boy 原理一樣?
錯了。絕對不一樣!
I am loving you 是 "現在進行式"，但文法錯誤. "love" (解"愛情"時) 不能有"進行式" (continuous tense)。


3. I am flying.
動詞+ing = present participle 現在分詞
現在分詞 除了表達現在進行時態，一般亦可作形容詞。
The object is flying. ~ a flying object
The teacher is dancing. ~ a dancing teacher

2014-09-06 00:18:12 補充：
(1) 另一說法
句子結構： S + LV + predicative prepositional phrase (ppp)
where "ppp" can be adjectival (like "in love") or adverbial (like "in Hong Kong").

Adjectival:
Tom is a man in love.
This is the list of World Heritage in danger.
I arrived home to find the house in chaos.

2014-09-06 00:31:16 補充：
另一句子結構： S + LV + predicative clause

Example: This is when it happened. ("when it happened" is adverbial clause)

When you consider all the aforesaid 句子結構 as predicative expressions, the verb is classified as linking verb (copula).

2014-09-06 00:54:43 補充：
re.: 意見005

If "be" is considered as intransitive verb (cf. Oxford), it is definitely correct to refer to the sentences as the suggested pattern; such as:
I fall in love.
I live in Hong Kong.

But, I think "in love" is an adjectival phrase.

2014-09-06 01:07:20 補充：
"fall", when means "become", must be followed by (1) adjective, (2) noun or (3) prepositional phrase (into something).

(1) fall ill; fall asleep; fall in love
(2) fall prey to
(3) fall into disrepair

2014-09-06 01:58:55 補充：
In MacMillan dictionary,

"be" is mostly considered as Linking Verb - used for giving information about someone or something, by giving their name, job, position etc, describing them, or saying where they are

It is intransitive only when it means "to exist".

2014-09-08 23:57:17 補充：
Relative clause (adjectival modifying "a man") reduces (by removing the relative pronoun and linking verb) into a phrase which also adjectival modifying the same noun "a man".

Tom is a man (who is) in love.

"in" (preposition).~ used to talk about the state or situation of something or someone
Pattern:
verb + in + noun

Examples:~ in chaos, in danger, in doubt, in love, in tears, in trouble

2014-09-05 08:58:03 補充：
I am in love.
I am in Hong Kong.

Sentence pattern:~ subject + intransitive verb + adverb/preposition

I ~ subject
am ~ intransitive verb, 不是 linking verb

in love 和 in Hong Kong 都屬于 prepositional phrase
不是形容詞, 不是 adjective predicate

prepositional phrase functions as an adverbial phrase.

2014-09-05 09:41:58 補充：
I am ill.
subject + linking verb + subject complement

I ~ subject
am ~ linking verb
ill ~ predicative adjective

subject complement 可以是 adjective (phrase) 或 noun (phrase)

2014-09-05 10:08:58 補充：
I am in Hong Kong.

有字典當 am 是 linking verb. ~ Merriam Webster
am 是 intransitive verb ~ Oxford ((OALD), Longman, Yahoo

He is a man of integrity.
is ~ linking verb
man of integrity ~ noun phrase, subject complement
of intrgrity ~ prepostional phrase functions as an adjective phrase,
形容 man

2014-09-05 10:31:08 補充：
Reference:

Thr principal is in his office. (is ~ i. v.) ~ Longman, Yahoo
She has been in her room for hours. ("has been" ~ i.v.) ~ OALD
Katrina is in her office. (is ~ i. v.) ~ Oxford student's Dict.
He is in the living room. (is ~ link. v) ~ Merriam Webster

2014-09-07 08:43:50 補充：
不同的字典與不同的人分析不同

fall in love = 墜入愛河
牛津與 Longman 將 fall 當 intransitive action verb (墜入)
in love 是 prepositional phrase

Are you falling in love? ~ continuous tense is acceptable
state verb 很少用 progressive form.

linking verb 後面一定是 adjective (phrase) 或 noun (phrase)
I fall. ~ OK

2014-09-07 08:49:03 補充：
fall asleep. fall ill

fall 容易理解和可接受是 linking verb (除了牛津)
因為 asleep, ill 是 adjective
同時沒有"墜入", "下跌", "陷入" 含意
fall asleep = to start to sleep
fall ill = become ill

我們從不同角度去看 "fall in love" Thanks for the contribution.

2014-09-07 19:54:02 補充：
She doesn't want to fall in love easily.
She is afraid to fall in love.
She is falling in love.
He can't help falling in love with that girl.

以上句子, 如果 fail 視為 intransitive verb , 比較容易理解
純個人意見

2014-09-07 20:02:35 補充：
當 prepositional phrase functions as an adjectival phrase,
多數是 after the noun it modifies, 少有 after the verb.

"Tom is a man in love. " ~ by 回答者

加ing的動詞

可以是動名詞

gerund

2014-09-04 19:46:14 補充：
動名詞是一「可數名詞」

noun