1 thick fog

1 smoke

2 mist

3 vapor

4 smog

5 fumes

1 to unlock

2 to release

1 to interlock

2 to be linked

3 chain (store etc)

1 to lock up

2 to lock

3 lock

4 classifier: 把 bǎ

1 One key opens one lock.

2 There is a different solution for each problem. (idiom)

1 lit. fettered by fame and locked up by riches (idiom); tied down by reputation and wealth

2 the victim of one's own success

1 to swallow clouds and blow out fog (idiom)

2 to blow cigarette or opium smoke

1 lit. to become lost in a fog (idiom); fig. at a complete loss

1 as if lost in a thick fog (idiom)

2 in a fog

3 muddled

4 completely unfamiliar with sth