Q: If He is one of those people who wants to see good things happen to good people., can we say that "He likes to see good things happen to good people."?

A: yes

Q: If , selling postage stamps, rating and receiving parcels, etc.);, can we say that "Many new systems have been improved, including the process of selling postage stamps."?

A: it is not possible to tell

Q: If like one night and the next night they'll stay at the motel you know or something like that and they enjoy it, can we say that "They never stay at motels."?

A: no

Q: If He poured some kefir into himself, and then by mistake into the vat., can we say that "He accidentally poured it into the vat."?

A:
yes