If the moon passes in front of the sun once a month, why don't we have monthly solar eclipses?

https://amp.space.com/25644-total-solar-eclipses-frequency-explained.html

How we managed what Einstein thought was impossible – and used his theory to weigh a star

https://theconversation.com/how-we-managed-what-einstein-thought-was-impossible-and-used-his-theory-to-weigh-a-star-79050?utm_medium=email&utm_campaign=Latest%20from%20The%20Conversation%20for%20June%208%202017%20-%2075765879&utm_content=Latest%20from%20The%20Conversation%20for%20June%208%202017%20-%2075765879+CID_eadefb5909822bae467d3ac1f72bb0d7&utm_source=campaign_monitor_uk&utm_term=measured%20this%20effect%20on%20a%20star%20other%20than%20the%20sun