—Is this your baseball, David?   —No, it's not     . It's Helen's.

____________of the twins passed the exam because they worked hard at their lessons. 　

—______is the Changjiang river in China, do you know?—Yes, it’s about 6,380 kilometers long.

One of her eyes is hurt, but her _____ eye is OK.

---Mum, ______ is my friend, Kate.---Nice to meet you.