---In recent years problem of global warming has been very serious.-That’s right. Peo

问题补充：

---In recent years, problem of global warming has been very serious.

---That’s right. People are facing number of natural disasters now.

A. the; a

B. a; the

C. a; a

D. the; the

答案：

解析：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。