$\text{@su}$
`6`, He started to play the piano five years ago.
(start + to V / V-ing : bắt đầu làm gì)
`7`, Tim was hungry because he had not eaten all day.
(because + clause : bởi vì...)
`8`, While I was opening the letter, the bell rang.
(cấu trúc "hành động chen ngang)
`9`, It snows quite much in Britain during the winter.
(miêu tả hành động hoặc sự việc thường xảy ra vào 1 thời điểm nhất định)
`10`, They were the poorest people I had ever seen.
(S1 + tobe + the adj-est/most adj + S2 + have/has/had + ever + P2)
$\text{#BTS}$