Contingency Plans with "Caso"
In Portuguese, we use the conditional conjunction caso (in case, if) to talk about hypothetical situations and contingency plans—such as what to do during an emergency.
Because caso introduces an event that is only a possibility and has not actually happened, it always triggers the subjunctive mood. Notice how the regular verb ocorrer (to occur) becomes ocorra and soar (to sound) becomes soe in the present subjunctive:
| In case an earthquake occurs, we stay under the table. | Caso ocorra um sismo, ficamos debaixo da mesa. |
| In case the alarm sounds, you have to leave the building. | Caso o alarme soe, tens de sair do prédio. |
The Subjunctive of "Haver"
When preparing for emergencies, you will frequently need the verb haver to say "there is" or "there are" (e.g., a fire, a power outage). In the present subjunctive, the impersonal haver takes the highly irregular form haja:
| In case there is a power failure, we use the generator. | Caso haja uma falha de eletricidade, usamos o gerador. |
| In case there is a fire, where is the fire extinguisher? | Caso haja um incêndio, onde está o extintor? |
Sentence Structure and Instructions
A caso clause can appear at the beginning or in the middle of a sentence. When it comes first, separate it from the main clause with a comma.
The main clause often contains an indicative verb stating a fact or plan, or an imperative verb giving an instruction (a command). Watch how the main clause in the first example uses an indicative verb, while the second example issues a command (pede):
| We want to buy a generator in case there is a power failure. | Queremos comprar um gerador caso haja uma falha de eletricidade. |
| In case you do not understand the instructions, ask for help. | Caso não compreendas as instruções, pede ajuda. |
