Question

---In recent years, _____ problem of global warming has been very serious.
---That’s right. People are facing ____ number of natural disasters now

1. A.
   the; a
2. B.
   a; the
3. C.
   a; a
4. D.
   the; the

Answer 1

A
考查冠词的用法。第一空是特指全球变暖的问题，所以用the,第二空为固定短语：a number of 许多，后用可数名词复数。the number of什么的数量，句意：在最近几年，全球变暖的为题已经很严重了。是的，人们正在面临许多自然灾难。所以选A。