Is __ your brother?

---Carl, why not go and help your sister water the flowers there?  ---Why__________? I’m busy myself. Jack is lying on the grass doing nothing.

— Do you like talking with your friends on the telephone or mobile phone?—          . I enjoy chatting online.

Mum, my trousers are too old. I want to buy a new ______.

—Have you finished your work yet?—No，not yet. I think it’ll take ________ minutes.