题目

----- In recent years,___ problem of global warning has been very serious.        ------That’s right. People are facing ____ number of natural disasters now.           A. 不填;   B. a; the   C. the; a  D. a; a 答案：C 解析: 考查冠词。全球变暖的问题是特指，a number of，许多，为固定表达。11．Boys and girls，keep quiet please．I have __________ to tell you（　　）A．important somethingB．important nothingC．something importantD．nothing important