Tigers are endangered animals.There aren't many of them____

Tigers are endangered animals.There aren't many of them____
A.leave B .to leave C.left D.to be left
答：C.
译：老虎是濒危动物.现在剩下的不多了.
分析：此题考非谓语动词作定语的用法.
there be 句型的主语（名词或代词）在be后,其后置定语可以是分词或不定式.分词有两种句式.
1.there is sb.doing sth.如：
There is a man waiting for you at the school gate.
校门口有一个人在等你.=There is a man who is waiting for you at the school gate.
现在分词的逻辑主语是man,他与wait是主动并进行的关系.
2.there is sth.left.如：
There is only 5 minutes left.
只剩下5分钟了=There is only 5 minutes which is left.
过去分词left的逻辑主语是5 minutes,它与leave 是被动（被剩下,被留下）的关系.
there be句型中,也有用不定式作定语的：
There is sth.to do/ to be done.有一些事要做（要被做）.不定式的动词应为及物动词,它与sth.有动宾的关系.表示“未来”.
本题中从形式上CD都可以,但不合句意,不合逻辑.（没有多少老虎要留（被留）下）,说不通.