The girl who had the virus

An nighean air an robh a' bhìoras

Take a look at the following sentences: 

'S e seo am balach aig a bheil ceann goirt.
This is the boy who has a sore head/headache. [lit. This is the boy at whom is a sore head/headache]
B' e siud an nighean air an robh a' bhìoras.
That was the girl who had the virus. [lit. That was the girl on whom was the virus]
Nach i an tè air an robh falt purpaidh an–dè?
Isn't she the woman who had purple hair yesterday? [lit. Isn't she the woman on whom was purple hair]

Do you remember the clàsan (clauses) we saw in SpeakGaelic A2? We learned how to introduce clauses using a (who, which, that) and negative clauses with nach (who, which, that not). However, when we have a preposition in the clause, 'on whom', 'to whom', we need to use a clàs roimhearach (prepositional clause). You can see the prepositions and the dependent verb in these tables: 

THA  A BHEIL?  BHA  AN ROBH? BIDH  AM BI? 
 … air a bheil …    … anns an robh …   … aig am bi …  
 … air nach eil …    … anns nach robh …   … aig nach bi …  
TRÀTH CAITHTE   PAST TENSE  TRÀTH TEACHDAIL  FUTURE TENSE  
BHRUIDHINN   AN DO BHRUIDHINN? BRUIDHNIDH  AM BRUIDHINN? 
 … ris an do bhruidhinn …   … ris am bruidhinn …  
 … ris nach do bhruidhinn …   … ris nach bruidhinn …  
DH'ÈIST   AN DO DH'ÈIST? ÈISTIDH  AN ÈIST? 
 … ris an do dh'èist …   … ris an èist …  
 … ris nach do dh'èist …   … ris nach èist …  
CHOIMHEAD   AN DO CHOIMHEAD? COIMHEADAIDH  AN COIMHEAD? 
 … air an do choimhead …   … air an coimhead …  
 … air nach do choimhead …   … air nach coimhead …