pleasehelp“Is the verb after there always a plural or singular form?”
It can be either singular or plural. It depends on the following noun phrase.
There is a seat.
There are seats.
There has to be a seat.
There have to be seats.
With a compound noun phrase having a singular first element, either singular or plural is possible.
There is a cat and a dog in the kitchen.
There are a cat and a dog in the kitchen.
There is a cat and some dogs in the kitchen.
There are a cat and some dogs in the kitchen.
CJ