Ik spaar pennen. Ik heb er al drie. quantitative
I collect pens. I’ve got three already.
ER in this sentence refers to a number, so this is quantitative ER. Compare to sentence 4d) in the text.
Ik heb ervan gehoord. prepositional
I have heard about it.
ER here is used with a preposition. It is actually attached to it (see glossary if you’re not sure what a preposition is). So this is prepositional ER. Sometimes the preposition is not attached to ER, but can be found further up in the sentence:
Ik heb er nog nooit van gehoord.
Jan kent Amsterdam goed. Hij komt er vandaan. locative
Jan knows A’dam well. He’s from there.
ER here refer to a place, a location ( Amsterdam), so this is locative use of ER.
Ik heb één auto, maar Kees heeft er veel meer. quantitative
I have one car, but Kees has many more.
Here ER refers to a quantity, so we have a case of quantitative use again. Note that quantities are not only number, but also things like more, less, a lot, etc.
Er werd gedanst en gezongen. grammatical
There was dancing and laughter.
Here ER doesn’t refer to anything; it is only inserted for grammatical reasons because the sentence needs a subject. Therefore, this is grammatical use of ER.