问题
选择题
----- 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
答案：C
考查冠词。全球变暖的问题是特指，a number of，许多，为固定表达。