論理的関係の解読や意味内容の解釈結果に基いて文法を記述することには慎重でなくてはならない｡次の場合､関係詞節は条件を表わす副詞節であるという文法的記述が成立すると考える人はまずもっていなかろうと推測する｡

ifに導かれる条件節の代わりに関係詞節をよく用いる｡
   'Any boy who should do that would be laughed at'
   = 'Any boy would be laughed at if he should do that.'
(CURME, Syntax, 31-1)

総称的名詞句を修飾する制限的関係詞節は、条件節を用いて言い換えられることがある。
   People who want security shouldn't take a job in commerce. ['If people want security, they shouldn't take a job in commerce']
同じことが時には、総称的名詞句を伴うその他の制限的修飾要素について当てはまる。
   Careless drivers cause accidents. ['If drivers are careless, they cause accidents']
   Cars manufactured abroad are less expensive. ['If cars are manufactured abroad, they are less expensive']
(CGEL, 15.34 Note[i])

To be human is to err. ['If one is human, one will err.' (CGEL, 15.11)

ifに導かれる条件節の代わりに、疑問文の語順を用いることがある｡
   'Is any among you afflicted ? let him pray' (James, V, 13).
   'Don't you love Nature because she is beautiful ? He (i.e. , Thoreau) will find a better argument in her ugliness ' (James R. Lowell, Literary Essays, I, p.372).
   'You would see for yourself, were you here.'
   'Had I the time, I would go.'
   'There are other articles, to which, did time permit, we might draw attention.'
   'People will gather by hundreds outside a police court on the chance of catching a glimpse of a criminal ; do they see but a corner of his hat, they go away happy.'
   'Were I to be late, would you wait for me?'
   'Should you find them, kindly let me know.'
   'Would space allow, I should like to quote the notice in full.'
   ……　古い英語においては､こうした構造は今日よりずっとありふれたものであった。
(CGEL, 15.11)

   更に[2−12]、第六章第５節参照。