(2012·南京高二检测) Some people are worrying about the possibility _______ mobile phones could be responsible for a range of illnesses, from rashes (皮疹) to brain tumors.
---Why does Peter look upset? --- He is a newcomer to the class and is having difficulty ______ by his classmates.
Her question was so difficult that I could hardly make any _______ of it at all.
Human beings are different from animals _____ they can use language as a tool to communicate.
The house prices fell sharply at the end of last year, but ______ at the beginning of this year.
Sam has been appointed_____ manager of the engineering department to take _____ place of George.