關於英文文法的問題?

1.We human beings may live without clothes, but food and air are essential to our lives.這裡的We 為什麼可以直接接上human這個名詞啊？
human beings是主詞we的「限定性質的同位語」。human beings（人類）是複數的「複合名詞」（名詞＋名詞），兩個字合成一個「詞」。

2. [You’re probably up (most of the night)] cramming.這裡的cram為何是ing呢?
If you are "up," you are not in bed.（see p.1521 Collins Cobuild English Dictionary for Advanced Learners）
cramming是用來修飾述部are up的「修飾語」，屬副詞性質的「現在分詞」。與述部「同時發生」：即熬夜時，是在K書（cramming =強記功課）。如：The boy is cramming (up) history.＝這男孩在背歷史。
You're probably up most of the night cramming.你大概晚上的大部分時間都在熬夜苦讀吧。（動詞時態用timeless present的are，因為常發生）。熬夜＋苦讀。

類似的副詞性修飾語，如：
The little girl came "running."
I like to stay home "reading novel and listening to music."

1. We human beings may live without clothes,but food and air are essential to our lives.
"human beings" is a noun phrase, which acts as a "restrictive appositive noun" to rename specifically (or add more information to) the subject "We" in the sentence.

(note: unlike non-restrictive apposition noun, restrictive apposition noun doesn't need commas to set off the subject and its predication)

2. You’re probably up most of the night cramming.
~ "cramming" is the present participle of the intransitive verb "cram" (~ to learn a lot of things in a short time - Oxford Disctionary).
~ "up" is an adverb, meaning "out of bed". (example: stay up)

"cramming", as well as the infinitive phrase of "cram", functions in the sentence as an adverbial ( not ＜主詞捕語＞) to state the PURPOSE of "being up" or "staying up".

e.g. She stayed up most of the night to cram for the exam.

We，與human beings 是同位語，同是當主詞用。
night cramming其中名詞night當形容詞修飾動名詞cramming，而cramming是不及物動詞所以不需受詞，此處為熬夜意思。你可能大部分時間都在熬夜吧。
另一種是動名詞當形容詞修飾名詞用，如washing machine，我們統稱此種二個名詞組成一個名詞為複合名詞

[◆ 我希望您－施捨文字的評價(意見)，只要您自認客觀的，適不適當都歡迎。]
● "human beings" 係 "we(代名詞)" 的同位語， 兩者組合成『主詞』。
# 同位語(Appositive)：1. 緊跟在名詞或代名詞之後說明該名詞或代名詞是指何人或事物或內容的語詞即稱為同位語。(2, 3.略。)
# human [名詞]：1. ((通例 humans)) ((話)) 人，人間. ◆一般には HUMAN BEING を用いる.
# human being：釋義2. (特に動物と対比して)人間 例. living conditions not fit for human beings 人間に適さない生活条件.
● You’re probably(副詞) up(形容詞) [most of the night](名詞) cramming. ←形容詞修飾名詞，並被副詞修飾，而(成副詞片語)修飾動名詞。 你很可能在大多數的夜晚臨時抱佛腳(苦讀)。
# You’re cramming(動名詞). ←現在進行式，表現在常態。你臨時抱佛腳。
# up most of the night 在大多數的夜晚。
# up [形容詞]：釋義-1.〈一定の時間・期間が〉終わった，終了した，切れた；((英)) 〈議会が〉休会［散会，閉会］した 例1. Time's up. 時間が切れた，それまで 例2. Your hour is up. あなたの持ち時間は終わりです 例3. The game is up. 試合は終了した.

1. We human beings ...
就像在中語裡面＂我們美國人．．．＂也是把兩個對等的名詞合起來用　（而不需要連接詞）當主詞用．
類似的用法：
你們這群野蠻人．．．＝You barbarians...

2. cramming (用功讀書的動作）在這裡是現在分詞當＜主動形容詞＞的＜主詞捕語＞
原句的意思是：

你大概是整晚熬夜　用功讀書吧？！？