---Is it worth the effort?

---______, yes．

---I hate to hear words as his.

---I don't think he ______ harm to you, though.

---I hear some scientists are afraid that computers will take the place of man, having humans as their slaves．

---What if that is the _________?

---Our new teacher’s English is difficult for me to ________．

---Why don’t you ask your brother ________ help?

---It seems that you want to say something to me.  

---Yes. Ask for a receipt and ________ that you get it.  

---How much do we have to pay for the gift?

---You can get them ________ free．

---Thank you very much.

---Not at all. It is ________ my duty as yours.

---You may talk to your friend on the phone.

---But I think it difficult to ________ about that by telephone.