ZERO CONDITONAL

If clause	Main clause
If + Present tense	Present tense
If you freeze water	it turns into ice.

• If you freeze water, it turns into ice.
• If I work too much, I get tired. 
• If I have time, I usually go to the movies.
• If she doesn't know the answer, she keeps silent.

Sherton

Conditional Connectors/links
if - si 
whether - si
unless - a menos que
provided / providing - siempre que, mientras 
as long as - siempre que, mientras 
in case - en caso de que