Select all that apply: which sentences correctly express an unreal or unlikely present situation?
If Mara knew sign language, she would help at the reception desk.✓Respuesta correcta
If the river were cleaner, residents would swim beside the old mill.✓Respuesta correcta
If Mara would know sign language, she would help at the reception desk.
If the river is cleaner, residents would swim beside the old mill.
Explicación
The language and river sentences both use a past-form condition with a would result. The rejected sentences place would in the condition or mix a present condition with a hypothetical result.