When

bao giờ

(at what time, as a direct question)

bao giờ

(at what time, as an indirect question)

khi nào

(at what time, as a direct question)

bao giờ

(at what time; at which time)

khi

(during the time that)

khi

(at what time; at which time)

khi

(since; given the fact that; considering that)

khi nào

(at what time; at which time)

lúc nào

(at what time; at which time)

khi nào

(the time)