Here are some sentences, would anyone please tell me which one is gramatically correct?
1. A thousand trees have been cut down.
2. Thousands of trees have been cut down.
3. A few thousand trees have been cut down.
4. a few thousands of trees have been cut down.
5. Many thousand trees have been cut down.
6. Many thousands of trees have been cut down.
I am quite sure the 1st two are correct, but not sure the last 4.
Thank you for help.
1. A thousand trees have been cut down.
2. Thousands of trees have been cut down.
3. A few thousand trees have been cut down.
4. a few thousands of trees have been cut down.
5. Many thousand trees have been cut down.
6. Many thousands of trees have been cut down.
I am quite sure the 1st two are correct, but not sure the last 4.
Thank you for help.