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.
eras, therefore concluding that its crust is harboring up to three times as much water than was
eras, therefore concluding that the planet's crust harbors up to three times as much water or more as was
eras and have therefore concluded that the planet's crust harbors up to three times as much water as
eras and they have concluded, therefore, that its crust harbors up to three times as much water, or more, than
eras and concluded, therefore, that the planet's crust is harboring up to three times more water as was
therefore是副词,不能连接两个句子。
错选B,在一道题里,如果只有分词ing的形式不同,那么通常从句+动词的形式>分词ing形式,因为可以更清晰的表达时态的变化。
C正确,have found 和 have concluded平行
登录 或 注册 后可以参加讨论