THAT SHOULD NEVER BE OMITTED.
The word that is very often omitted in English, but should NEVER be omitted in Ido:
(1) The book I gave you (= the book that (or which) I gave you).
La libro quan me donis a vu.
(In this case that is the pronoun.)
(2) I think he will come (= I think that he will come).
Me opinionas, ke il venos.
(In this case that is the conjunction.)
It is generally omitted in English after verbs like to think, to hope, to wish, to
believe.
It is impossible to pay too much attention to this rule, as the correct use of the word
ke is the key to a good international style for English-speaking students.
OTHER WORDS OMITTED.- All other words omitted in English have to be inserted in Ido:
It was he mentioned the fact (= he who mentioned).
Il esas ta qua mencionis la fakto.
He knew the man we were speaking of (= of whom we were speaking).
Il konocis la viro pri qua ni parolis.
Do what he will (= let him do ...), he cannot ...
Il facez quon il volas, il ne povas ...
If a man was great while living (= while he was living).
Se homo esis famoza, dum ke il vivis.
He gave the boy a penny (= a penny to the boy)
Il donis dek centimi a la puero.
Show it me (= show it to ne)
Montrez ol a me.
WHOSE, OF WHICH.- Whose and of which are translated di qua (or di
qui):
The boy whose book I saw (= the boy of whom I saw the book).
La puero di qua me vidis la libro.
The sword which Hector gave Ajax was that on whose point Ajax fell.
La glavo quan Hektor donis ad Ajax, esis ta sur la pinto di qua Ajax falis.
The books, the binding of which you liked.
La libri di qui vu prizis la binduro.
INFINITIVE CLAUSE.- Another case in which that as a conjunction (=ke) should be
used is the infinitive clause:
I want you to come, Me volas, ke vu venez.
He ordered them to go away, Il imperis, ke li de-irez.
It will be noticed that such phrases occur most frequently with verbs of command and
desire.