`1. →` Nowadays people can talk and exchange information easily thanks to technological advances. It is convenient
`2. →` it is such a pity that in this busy world parents and children don't have much quality time for each other
`3. →` It was very helpful that my neighbor looked after my pet cat when I was away for some days.
`4. →` By the time I left my hometown to go to university in 2010, this bridge had been built in my hometown
`5. →` Before my brother got married , he got a good job in a state bank
Cấu trúc "before":
-QK: Before + simple past, past perfect
-HT; Before + simple present, simple present
`+)`By the time + S1 + V1 (quá khứ đơn), S2 + V2 (quá khứ hoàn thành).