No "to" between two verbs

> "Let’s help push the cart across the bridge"
> 能解释下 "Help" and "push" 为什么能并列吗？

Most verbs need "to" to be inserted in front of the verb following it, e.g., "He told me to do it". There're a couple of verbs that don't need the "to", e.g., "He let me do it". And there's one verb that can, but doesn't have to, be followed by "to", and that verb is "help", e.g., "We can help you to finish the job", "We can help you finish the job". In fact, Americans often omit the "to" and I think more and more British do that too now.

In very informal English, people omit "to" after "go", e.g., "Let's go eat", or omit "and", e.g., "Go ahead do it".