• The most common equivalent of "but" is pero:
Hacía sol, pero también frío.It was sunny, but it was cold, too.
Note that when pero is used, the second phrase does not exclude the first.
• Sino follows a negation and means something like "but on the contrary" or
"but instead" :
No es tonto, sino demasiado inteligente.He is not dumb, but (rather) too intelligent.
• The Spanish equivalent of "not only...but (also)" is no solo ... sino (también):
El sistema no solo es eficaz, sino también agradable. The system is not only efficient, but also nice.
• The relative que must be used when sino introduces a clause with a conjugated verb:
|No solo cantaron, sino .
No , sino me en casa.
|Not only did they listen to music, but they also danced.
I did not go out, but (instead) I stayed home.