Underline the correct answer.
1. I write my composition ( on , by , with ) a pen.
2. We are going to the concert. Are you coming with ( me , us , you )?
3. Please give him some water ( why , because , since ) he is very thirsty.
4. The ( singer , singer's , singers' ) voice is very powerful. He is also a good performer.
5. The cat jumped ( in , over , under ) the low wall.
6. She was my teacher. I know ( her , him , she ) very well.
7. I don't understand ( when , what , why ) he didn't turn up for training yesterday.
8. The ( cat , cat's , cats' ) leg is badly crushed.
9. What ( is , are , were ) the size of your shirt?
10. Meilin has passed her examination ( since , because , then ) she worked hard.