ines de Enero: They have to finish
the work for the end of January.

Hemos de seguir los consejos de los peritos en la materia: We have to
follow the advice of those expert in the matter.

In such cases _Tener_ is followed by _que_ and _Haber_ by _de_.[155] The
former indicates compulsion or necessity, the latter a moral or
self-imposed duty.

_Haber de_ translates also "to be to,"[155] as--

?Quien ha de hacer este viaje? Who is to go on this journey?

_Tener de_ is used in threats--

Tengo de llevarlo ante el tribunal: I shall take him before the court.

"Tener que hacer, que escribir, que comer" and similar expressions
translate also "to have something to do, to write, to eat," as--

Hoy tengo que hacer: To-day I have something to do, I am busy.

Tengo mucho que hacer: I have much to do.

Tenemos que comer por todo el dia: We have something to eat which will
suffice for the whole day.

_Haber_ is used as a principal verb instead of _Tener_ in--

Haber menester de algo: To need something.

He aqui el muchacho, etc.[156]: Here is the boy (behold the boy here,
etc.).

Heme aqui _or_ heteme[157] aqui, etc.: Here I am (behold me here, etc.).

It also survives in some legal phrases, as--

Fue habido el reo: The culprit was captured.

Los hijos habidos en su primera mujer: The children by his first wife.

And in some idioms, as--

Alla se las haya: That is his business.

Haberselas con uno: To dispute with anybody.

_Tener_ translates the English "to be" in such phrases as--

Tener hambre, sed, sueno, calor, frio, vergueenza, and miedo: To be
hungry, thirsty, sleepy, warm, cold, ashamed, and afraid.

Also speaking of age--

Tengo veinte anos: I am twenty years old.

[Footnote 155: In all these cases _deber_ may be used instead.]

[Footnote 156: _He_--imperative mood of _haber_.]

[Footnote 157: The _te_ is the "ethical dative" (which is much more used
in Spanish than in English).]

And in--

Tener razon: To be right.

And--

No tener razon _or_ Dejar de tener razon: To be wrong.

We said that the past participle when used with _Tener_ agrees with the
direct object, as--

Tengo leidas las cartas: I have read the letters.

But when there is no direct object, of course the past participle
remains invariable, as--

Tengo entendido que....[158]: I have heard that....

[Footnote 158: This use of _tener_ for _haber_, especially with no
direct obj. following is in general to be avoid