Historical clue formulations

• Enter smoothly — 2022-06-26
• Gradually become familiar with — 2020-12-05
• Take on gradually — 2012-07-27
• Take on gingerly — 2009-09-25
• Not enter hurriedly — 2005-03-18
• Gradually become part of — 2001-03-16
• Become familiar with gradually — 1999-04-02