The sun had set by the time she arrived home.

Meaning: The sun had gone down by the time she got home.

Choice of Words: Set means to cause something to sink or fall to a lower position. Arrived means to reach a place.

Alternative Expressions

When she got home, the sun was already down.

Meaning: This sentence tells us the same thing as the first sentence, but it uses different words.

Choice of Words: When means at the time that. She is a pronoun that refers to a female person. Got is a verb that means to arrive at a place. Home is the place where someone lives. The sun is the giant ball of fire in the sky that gives us light and warmth. Was already down means the sun had already set and it was getting dark.

It was dark outside when she finally reached her house.

Meaning: This sentence tells us the same thing as the first two sentences, but it uses different words and it emphasizes that it was dark outside when the girl got home.

Choice of Words: It is a pronoun that refers to something that has already been mentioned. In this case, it refers to the time of day. Was dark means there was no light outside. Outside means not inside a building. When means at the time that. She is a pronoun that refers to a female person. Finally means at last or after a long time. Reached means arrived at a place. Her house is the place where she lives.

Related Expressions