Helen has two sisters and a brother. Her brother is working, but _________her sisters are still at school.

I find           easy to learn English.

—______was your trip to Mount Emei, Alice?一 It was great! We-really had a good time there.

I forget to bring a pen, would you lend me ____?

--- Is this your sister’s key, John?--- No, it isn’t. ______ is in the bag.