(The) Leaves on the trees

[sitifan]

1. Leaves on the trees are yellow and orange.
2. The leaves on the trees are yellow and orange.
What's the difference in meaning between the above two sentences?

[2006]

1. Leaves on the trees are yellow and orange.
2. The leaves on the trees are yellow and orange. They are specific leaves, the ones on the trees we are talking about.
What's the difference in meaning between the above two sentences?

2006

[2006]

But #1 is quoted from an English textbook published in Taiwan.

#1 is an odd sentence; I can't think of a scenario in which I would use that sentence.

[2006]

3. Girls in this class are lovely.
4. The girls in this class are lovely.
What's the difference in meaning between the above two sentences?

2006