Question

1. The ball under the desk are some.
(Is this correct?)

2. When is your birthday?
2-1. It is January 25th.
2-2. It is on January 25th.
2-3. My birthday is on January 25th.
2-4. My birthday is January 25th.
(Which answer is correct? Are all correct?)

Answer 1

#1 makes no sense at all. First, ball is singular, are is plural and some is plural.

All of #2 are correct

Answer 2

Thank you. Then, what about the following?

The balls under the desk are some.

(Is it correct? If not what expressions do we have to use?)

Answer 3

Yes, that is far far better! However what do you mean by "some?"

Sra