--Growing population resulted in growing rubbish.
--There is possibility that rubbish the major threat to human beings.
A. bees
B. is being
C. became
D. would bee
网友回答
A. bees
(答案→)B. is being
C. became
D. would bee
解析：
试题分析:考查动词时态。根据语境可知此处是对未来的预测，所以用现在进行时态表示将来。句意：--逐渐增多的人口造成了越来越多的垃圾。---有可能垃圾会成为人类最大的威胁。