以下兩組兩句有咩分別?

全部都係 passive voice，全部都冇錯。
1.1 ...should have been cleaned o既 active voice 係 should have cleaned ，意為「應該已經清潔左」。另一重意思係馬後炮：「應該早ｄ清潔左間房就好啦。」呢個意思睇埋上文下理就知道係唔係原意。
1.2 ...should be cleaned ，即係「應該要清潔」，言下之意就嫌依家污糟。
2.1 ...has been cleaned，active 為 Paul has cleaned...，現在完成式，用於講剛發生o既事，或者發生後效果持續至今o既事，意為「Paul 已經清潔左房間」，言下之意，「間房依然乾淨」。
2.2 It is cleaned...，active 為 Paul cleans it，簡單現在式，用於講一ｄ現時發生o既事或慣常做o既事。呢句意為「Paul 負責清潔呢間房o既」，可以係講呢個係 Paul 今次偶一為之做o既事，亦可以係 Paul 日常工作就係清潔呢度。要確定就要知 Paul 做邊行，係咪酒店執房？即係又要睇上文下理啦。

11 ...should have been cleaned o既 active voice 係 should have cleaned ，意為應該已經清潔左。另一意思：應該早ｄ清潔左間房就好。12 ...should be cleaned ，即係應該要清潔

21 ...has been cleaned，active 為 Paul has cleaned...，現在完成式，用於講剛發生既事，或者發生後效果持續至今既事，意Paul 已經清潔房間，意，間房依然乾淨。

22 It is cleaned...，active 為 Paul cleans it，簡單現在式，用於講一ｄ現時發生既事或慣常做既事。意Paul 負責清潔呢間房既，可以係講呢個係 Paul 今次偶一為之做既事，亦可以係 Paul 日常工作就係清潔呢度。

1(1)The room should have been cleaned.
係解(房間應該被清潔了)
(2)The room should be cleaned
係解(房間應該被清潔)

2(1)It has been cleaned by Paul
係解(被保羅清潔了)
(2)It is cleaned by Paul
係解(被保羅清潔)

兩組的第一句是現在完成式的passive
第二句是現在式的passive

全部都冇錯,各在不同的意思.

1(1)是指這房應該已被清潔(即已經清潔咗,是說話人的判斷)1(2)是指這間房應該要清潔(即說話人覺得間房唔乾淨,所以認為要清潔.

2(1)中,我假設你仍是指房吧,是指這房是Paul清潔的,Past Perfect Tense是用來表示過去某個時間的動作.2(2)是Present Tense,即指Paul在清潔這間房.

1 (1) The room should have been cleaned.係錯既
(2) The room should be cleaned.係啱既

2 (1) It has been cleaned by Paul.係啱既
(2) It is cleaned by Paul.係錯既