这是一个复合句，前半部分描述现象（时间快、不等人），后半部分通过“therefore”引导出逻辑结论（要珍惜），逻辑严密，表达清晰。
Time flies like an arrow, urging the aging process; days and months shuttle by, chasing the youth away.
Only by grasping today can we open up tomorrow.
Time is like life; every moment is worth a thousand pieces of gold.
Time flies swiftly, and years never wait for anyone; therefore, we should cherish every moment.
A year's plan lies in spring, and a day's plan lies in the morning.
In youth, the mind is focused and memories are strong; in age, the spirit wanders and focus is easily lost.
Time is a great writer; it can write the ending of the future.
Learning lies in consistent, small efforts; we should even cherish every second.
One present moment is worth more than two tomorrows.
光阴似箭催人老，日月如梭赶少年。
只有把握住今天，才能开创明天。
时间像生命，一刻值千金。
时光飞逝，岁月从来不等待人，因此我们应当珍惜时间。
一年之计在于春，一日之计在于晨。
少则志一而难忘，长则神放而易失。
时间伟大的作者，她能写出未来的结局。
学问在于点滴勤，吾辈更应惜秒阴。
一个今天，胜于两个明天。