# Být + instrumental case



## artimedoros49

Hello,

I know that the topic of “být + instrumental” has been previously discussed, but I have another question regarding this usage.
In my text, _New Czech Step by Step,_ there is an exercise on the Instrumental /7th case, with several sentences to complete.
1.    Nůž a nůžky jsou *nástroji. *(7th case (s.))
2.    Židle, postel, stůl a skříň jsou *nábytkem*.  (7th case (s.))
3.    Auto, autobus, vlak …jsou *dopravními prostředky*. (7th case(pl.))
4.    Lžíce, vidlička, nůž a lžička jsou *příbory.* (7th case (pl.))

According to Janda & Townsend, (_Czech,_ p.82; 3.1.7.2):  “With forms of the verb “být” ‘be’ the instrumental can be used to *express a category* that an item belongs in, giving it a label, such as: „_Velryba je *savcem“*,_ ‘The whale is a mammal’, „_Velbloud je na poušti_ *dopravním prostředkem“,* ‘In the desert the camel is a means of transport’.

I see that nástroj, nábytek, prostředek and příbor*, *are a category or class that the other items belong to, but what I don’t understand whether they should be 7th case singular or plural. I used the singular for all of them, apparently incorrectly. (Corrections are as above). I would have thought that in this situation, where the predicate  = a class or category, it would consistently be either singular or plural. Thus, to expand Janda’s example:_ Velryba je *savcem *_(7th case (s.)),_ Velryba, lev a opice jsou *savcem/savci.*_?? If anyone could explain this to me, I would be very grateful.

Thank you


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## Mori.cze

Hello artimedoros,

actually the rule is very simple and consistent:
velryba (sg) je (sg) *savcem *(sg)
velryby (pl) jsou (pl) *savci *(pl)
velryba a lev (2*sg = pl) jsou (pl) *savci* (pl)
velryby a lvi (pl) jsou (pl) *savci* (pl)

so, as you see, the declension is governed by the subject quite the same way as in nominative (which is by the way the case I would generally prefer in those cases)

Edit: your confusion seem to come from _nástroji_ (which actually is plural), and _nábytkem _(which indeed is singular, but comprises not just one piece but rather the collective of furniture and as such has no plural form)


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## artimedoros49

I begin to see (I think). If, as in (2) above, the predicate is a collective noun, then it will be 7th case singular. However, in another sentence I wrote „_Tričko, šaty, kalhoty...jsou *oblečeními (pl.)*_“, which the teacher corrected to *oblečením (s*). Does this mean that in this context *oblečení *means „clothes“ as a collective noun, therefore use the singular,  but if, say, the noun had been qualified by an adjective e.g., „*sportovní  oblečení*“, then perhaps the meaning would change: _Tričko, šaty, kalhoty...jsou* sportovními  oblečeními, *_ie, they are sporting garments, therefore use the plural?


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## Mori.cze

artimedoros49 said:


> ... I wrote „_Tričko, šaty, kalhoty...jsou *oblečeními (pl.)*_“, which the teacher corrected to *oblečením (s*). Does this mean that in this context *oblečení *means „clothes“ as a collective noun, therefore use the singular...


  yes, exactly.

_Oblečení_ as such does not really have a plural, if you want to specify talking about more than one garments, you would use something like "kusy oblečení" (much like _informations _in English)



artimedoros49 said:


> _Tričko, šaty, kalhoty...jsou* sportovními  oblečeními*_


  that does not really work (same way as _"travelling informations" _is no more correct that simple _informations_); to make the plural appear you would have to use e.g. _Tričko, šaty, kalhoty... jsou* druhy/typy/kusy oblečení.*_


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## artimedoros49

Thank you so much for explaining all that, Mori.cze.


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## bibax

„_Velryba je *savcem“ *_ ‘The whale is a mammal’
„_Velbloud je na poušti_ *dopravním prostředkem“*  ‘In the desert the camel is a means of transport’.

Velryba je ssavec. _- nominativ_
Velbloud je na poušti dopravním prostředkem (v ZOO není dopravním prostředkem). _- instrumentál_

Petr je hrbáčem. 
Peter je ředitelem školy.


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