(2) Vocabulary Time

era

a long period of history with particular characteristics (thời đại, kỉ nguyên)

eternal

lasting forever (vĩnh cửu, bất tận)

(informal disapproving) continuing all the time without changing, or happening again and again, in a way that is annoying (triền miên)

expire

to come to an end or become no longer valid (hết hạn)

(formal) to die

frequency

how often something happens (tần suất)
(physics) the number of times that a waves, especially a light, sound or radio wave, vibrates in a second. (tần số)

instantaneous

happening immediately (tức thời)

interim

temporary and intended to be used until something permanent exists (tạm thời, lâm thời)
the period between two events (giai đoạn chuyển tiếp)

interval

a period of time between two events (khoảng thời gian giữa 2 sự kiện)
a short period between the parts of a performance or a sports event (giờ nghỉ giải lao của kịch/nhạc hội)

lapse

a temporary failure or interruption (sự gián đoạn, mất tập trung tức thời)
to come to an end because not continued (hết hiệu lực)
a period of time appsing by between two things happening

lifetime

the period during which a person is alive (suốt cuộc đời)

long-standing

Having existed for a long time.(Lâu đời, kéo dài từ lâu)