季节的交替给这片土地带来了不同的色彩。

The ___alternation of seasons brings various colors to this land.

昼夜的交替让我很难调整睡眠时间。

The ___alternation of day and night makes it hard for me to adjust my sleep schedule.

英语中动词sing和sang的交替形式表示了过去时态的变化。

The ___alternation between the verb forms ___sing and ___sang indicates a past tense change in English.