When you are done with the book, just give it to Lucy or Helen or ________.

---Do you have enough students to carry the boxes?---No. I think we need ______students.

Cars do cause us some health problems—in fact far more serious ________ than mobile phones do.

 - It's too cold. Can I spend _______ minutes in bed ,Mum? - Sorry, you can't. It's late.

Everyone knows that________ is dangerous to play with fire, but________ is difficult is to prevent children from playing with fire.