The switch between the two phases was hard to spot at the time, but probably happened in 2001-02.

2段时期的转折点很难界定，但有可能是出现在2001——2002年之间。

youdao

The switch between the two phases was hard to spot at the time, but probably happened in 2001-02.

2段时期的转折点很难界定，但有可能是出现在2001——2002年之间。

youdao