1 between

2 among

3 inter-

1 the human world

2 the earth

1 surname Ou

1 nighttime

2 evening or night (e.g. classes)

1 urban district

2 downtown

3 city center

1 one man can hold the pass against ten thousand enemies (idiom)

1 One key opens one lock.

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

1 hell on earth (idiom); suffering the torments of Buddhist hell while still alive

2 fig. having an uncomfortable time

1 to speak without thinking (idiom)

2 to blurt sth out

1 to start sth new or original (idiom); to break a new path

2 to break fresh ground