「今天很熱」,這句英文應該很簡單吧!但錯誤率非常高,檢查一下自己對了沒。假如你說的是這樣:
“Today is hot.” (X)
那就錯了。

今天很熱,昨天很冷,中文沒錯,但仔細想一下,熱的、冷的其實是「天氣」,主詞用it代表the weather,today/yesterday是時間副詞,放在句末,這樣說:
(O)It’s hot today. 今天很熱。
(O)It was cold yesterday. 昨天很冷。

就像外面下雨了,也不要說
(X)Outside is raining.
(O)It’s raining outside.

同樣的道理,想想「明天不上班」要怎麼說?
(X)Tomorrow will not work.
(X)Tomorrow is off.
(O)I am off tomorrow.
(O)Tomorrow will be my day off.

你明天不上學/班嗎?
(X)Is tomorrow off from your school/work?
(O)Are you off from school/work tomorrow?

我工作很忙。
(X)My job is busy.
(O)I am busy./I have been busy.
忙的是人,不是工作,所以主詞是”I”。

英文是一種邏輯很清楚的語言,特別是主詞,定義都非常明確。再來看幾個主詞錯誤:

車速很快。
(X)The speed is fast.
(O)The train travels very fast.
(O)The speed is high.
中文說速度快,但真正快的是車子,速度是一種客觀測量,在英文裡用high/low來形容。

他體重很重。
(X)His weight is very heavy.
(O)He is heavy

那價格很高。
(X)The price is expensive.
(O)The price is high.

三個月英文脫胎換骨的一對一:https://goo.gl/Z3q8QK