III.语法填空：(共10题，每小题1.5分，共15分）
People can call 911 when they need help. The police will come quickly. This phone number should be used only  26  an emergency. But there have been some problems with people using the 911 phone number.  27  than half of the calls made to it are an accident. These accidental calls are not real emergencies.
Calling 911 when you do not need  28  can be very bad. It wastes the time of the people answering the calls. It can even force someone  29  has a real emergency to wait before  30  (get) the help they need.
Many accidental 911 calls come from cellphones. Sometimes keys on the phone  31  (push) and the call goes through without the owner of the phone knowing that he has called an emergency number. People are trying to find  32  way to solve this problem.
They are testing a new program that might help solve the problem of accidental 911 calls. This program will make  33  (call) of 911 calls push another key on the phone  34  it is a real emergency. People hope that this change  35  (reduce) the number of accidental 911 calls going through.