I found ________ difficult to work out the problem without a computer.

—I’m a little nervous to give an English speech this afternoon.  —Come on ! Believe in ________  and you can do it.

—Do you know the man wearing a pair of glasses?—Yes. He’s a teacher of ________. He teaches ________ History.

Mr. Green didn’t post the letter _________. He asked his son to do it for him. 

----Who is _____ ?----_____­name is Betty.