1. Tell me why you are afraid.
2. We do not know what he is doing.
3. I do not know how many ships there were.
1. Dic mihi cur timeas (verearis, metuas).
2. Nescimus quid faciat.
3. Nescio quot naves (quantum navium) fuerint.
Feel free to discuss, correct, explain, and argue in a scholarly manner :D
Synopsis of material:
A Subordinate Clause is a ...