Complex sentences question

Question

I have 2 sentences that I don't understand:

1.) The girl [[sleeping]] in the room is my sister. 2.) People usually can get a sufficient amount of the calcium their bodies [[ need ]] from the food they consumed.

These 2 sentences have one verb already. (is for (1) and get for (2)) why they don't use the same.

And I heard that without the word "That" I have to use Ving after that, what is it? Where can I find the source to study.

Answer 1

These sentences have been done things to.
Put the pieces back together before you try to parse them.

Here are the full forms, with the bells and whistles put back in (and superfluous phrases snipped):

1. The [girl [who is sleeping in the room]] is my sister.
2. People can get enough of the [calcium [which/that their bodies need]] from their food.

(1) is a case of Whiz-Deletion from a relative clause, producing a post-nominal participial clause.
(2) is a case of a dropped non-Subject relative pronoun which/that; they're optional, after all.