选择表达正确的句子。

( ) 1. A. She is putting her pencils in her pencil case.

　　　 B. She is put her pencils in her pencil case.

( ) 2. A. He reading a book.

　　　 B. He is reading a book.

( ) 3. A. Where is Mr. Wood?

　　　 B. Where are Mr. Wood?

( ) 4. A. He is in library.

　　　 B. He is in the library.