标题: 有关scientists have found and have conclued这道题 [打印本页] 作者: LCY0508 时间: 2019-7-26 11:08 标题: 有关scientists have found and have conclued这道题 Scientists have found signs that moving water changed the chemical makeup of the surface of Mars in recent eras, therefore concluding that its crust is harboring up to three times as much water than was previously thought.
(A) eras, therefore concluding that its crust is harboring up to three times as much water than was
(B) eras, therefore concluding that the planet's crust harbors up to three times as much water or more as was
(C) eras and have therefore concluded that the planet's crust harbors up to three times as much water as
(D) eras and they have concluded, therefore, that its crust harbors up to three times as much water, or more, than
(E) eras and concluded, therefore, that the planet's crust is harboring up to three times more water as was
这里我想问下C和E
E中的concluded是省略了have，还是就是用了过去式，
C中从句的动词为什么是一般现在时harbors，和E的is harboring怎么判断选择
three times more water as was 改成 three times more water than 可以吗