求助一道关于单复数的问题！

yyisgreat

Environmentalists associated with the United Nations Environment Programme predict that if the current trends associated with global warming continue, thousands of acres of pristine land is in danger to undergo potentially irrevocable changes that could alter the planet's ecosystem forever.

	A)	is in danger to undergo
	B)	are in danger of undergoing
	C)	is in danger of undergoing
	D)	are in danger to undergo
	E)	are in danger for undergoing

答案是B,但是我觉得land不可数呀？为什么还是要用复数呀？

Fiona09

我觉得acres是核心词, 举例：a study of food resources  in the North Pacific reveals that....

yyisgreat

Fiona09 发表于 2016-8-19 18:06
我觉得acres是核心词, 举例：a study of food resources  in the North Pacific reveals that....  ...

那请问能不能有tons of water，这种表达呀？如果有谓语动词应该是单数还是复数哦？