______ parrots are native to tropical regions is unture.为什么答案是 That all 不是 All 呢

题目

______ parrots are native to tropical regions is unture.为什么答案是 That all 不是 All 呢
———— are kept as pets in almost every country in the world.为什么这里又应该选折Cats and dogs,而不是That cats and dogs.

答案

That后面引导主语同位语,all parrots are native to tropical regions是真正主语.句子主干是That is unture.
Cats and dogs用了名词的复数形式,是泛指猫和狗,表示一类动物用名词复数形式.that是特指某个事物了,后面也不能用名词复数形式.these后面可以用名词复数.