题目

1.At present,about 300 (different) varieties (of dinosaur) have been identified from (bones found) on (every) of the continents.
错误的是D,every.为什么?dinosaur不应该变成dinosaurs吗?
2.By 1996,the US population (exceeded) 261 million,with a median (age of) thirty-four,(making) it one of the oldest national (population) on earth.
错误的是D,exceeded 不用改成had exceeded吗?
3.Missouri is a (heavily) industrialized state (whose) (leading) products are transportation equipment,processed food,and (chemical).
为什么?

提问时间：2020-10-16

答案

1.every不能做代词,只能做形容词,所以当它用在介词of前面的时候,应该是every+名词+of...
跟它意思相近的“each”就可以做代词,所以这里应该用each.dinosaur应该也是用复数的,这里可能有两处错误.
2.by+时间,=no later than 不迟于…….不一定要用完成时的.
比如说：Be here by four o'clock.四点钟之前到这儿.
当然在那个句子里,我们肯定还是习惯用完成时态的.
3.chemical是形容词,前面几个并列的单词都是名词,所以改成chemistries