数学课上，老师向我们展示了数字序列的规律性递进。

In math class, the teacher showed us the regular ___progressions of number sequences.

这首歌的和弦进行很特别，让人印象深刻。

The chord ___progressions in this song are very unique and memorable.

数学老师解释了数列的逐步发展过程。

The math teacher explained the ___progressions of number sequences.