Is "(Ele) sunt tare si rece" wrong?
Ele is fine, both ei and ele mean they. Ele is just feminine whereas ei is masculine.
"ei sunt gru sunt rece"...can anyone tell me why this is wrong?
Greu = hard as in difficult, not for consistency
"Ei" is for the masculine gender and you should have used the masculine form of the adjective: tari, reci, etc. If you use "ele", the adjective changes to the feminine form: tare, rece.