[Grammar] Please help me to answer this question

[The Nightmare]

Is there any difference between "By 2005 people attending to organizations had increased" and "By 2005 people to attend to organizations had increased." ? ---- "To study lessons is necessary" and "Studying lessons is necessary"------ "The most important thing is helping people. and " The most important thing is to help people."

 

[emsr2d2]

Is there any difference between "By 2005 people attending to organizations had increased" and "By 2005 people to attend to organizations had increased"?
Neither is a correct sentence. We don't "attend organisations". We belong to organisations. We attend meetings, concerts, gigs, parties etc.

"To study lessons is necessary" and "Studying lessons is necessary".
We don't study lessons. We study. We take/have lessons in a subject.

"The most important thing is helping people. and " The most important thing is to help people."
Both are fine but I prefer the first.

See my comments above in red.