N5
その
That
そのパズルは難しい?
Is that puzzle hard?
Explanation
「その」 means 'that …' and must go before a noun: 「その時計」. It points to something close to the listener. In conversation it is very often used to pick up what the other person just said: if they say 「昨日、猫を買ったんだ」, you can answer 「その猫、何歳?」 (How old is that cat?).
Mixed up with
「その」 must be followed by a noun; on its own say 「それ」: 「それは時計です」.
For a new topic the other person just brought up, use 「その」, not 「この」 or 「あの」.