求解OG Verbal 语法70题~~

judy429

The gyrfalcon, an Arctic bird of prey, has survived a close brush with extinction; its numbers are now five times greater than when the use of DDT was sharply restricted in the early 1970s.
A. extinction; its numbers are now five times greater than
B.  extinction; its numbers are now five times more than

答案是A
其他选项我都能理解，但是greater 和more的区别我搞不清楚~
解释里是说"more" implies there are now more numbers, rather than more gyrfalcon.
Thx a lot！！