INFINITIVES AND GERUNDS AFTER A PREPOSITION:
A: What on earth is this?
B: Oh, that's called a "musical finder". It's the most wonderful new gadget on the market today!
A: Uhm, what's it for?
B: It's used for finding things. And it's terrific!
A: That's sound interesting.
INFINITIVES AND GERUNDS
A: Good afternoon, sir. May I help you?
B: Uh, something's wrong with this watch.
A: What´s the problem?
B: Well, it's stopped.
A: OK. let me have a look. Oh, the battery needs to be changed and the watch needs cleaning.