踩坑两次 一个小科普

1，In 1987 Saul Perlmutter at the Lawrence Berkeley lab in California, needing more Ia supernovae than visual sightings were providing, set out to find a more systematic method of searching for them.
{In 1987} Saul Perlmutter at the Lawrence Berkeley lab in California, {needing more Ia supernovae than [visual sightings were providing]}, set out to find a more systematic method of searching for them.
一时间竟然没找到主句的主谓，沉浸在自己最初的想法，were providing太像谓语了，而且提供这个词是人、是谓语是Saul Perlmutter发出来的好通顺呀，哈哈哈哈...。但其实是visual sightings were providing是一套主谓，是比较的内容。而Saul Perlmutter set out...才是主句主谓，needing是主句的伴随。