▲在表示时间的词语之前，若有了表示“大约”之意的about，around 时，有时可以省略有关的介词。例如：

(in) about 1980：

He referred to an incident that occurred about 1980. 他提到了大约1980年发生的一件事。
(for) about three days (weeks, months, years)：

I have been out of contact with her about three years. 我与她失去联系约有三年。

▲The band broke up about 1970, but happily they reunited in the mid-1980s. They produced a new record in 1996, with which they celebrated their former time as a real band. 

等于：The band broke up in about 1970, but happily they reunited in the mid-1980s. They produced a new record in 1996, with which they celebrated their former time as a real band.