ולכן

ולכן

"And therefore" or "and so."

Here, 'ולכן' connects the cause (studying all night) with the result (being tired in the morning).

היא למדה כל הלילה ולכן הייתה עייפה בבוקר.

She studied all night, and therefore, she was tired in the morning.

In this sentence, 'ולכן' is used to denote the consequence (getting wet) of the action (forgetting the umbrella).

הוא שכח את המטריה שלו ולכן נרטב בגשם.

He forgot his umbrella, and therefore, he got wet in the rain.

Here, 'ולכן' establishes a reason-result relationship between the two parts of the sentence.

הילדים חזרו מוקדם מהחוף ולכן התחלנו לאכול מוקדם יותר.

The children came back early from the beach, and therefore, we started eating earlier.