求助OG12第73题

meckychen

Combining enornous physical strength with higher intelligence, the Neanderthals appear to have been equipped to face any obstacle the environment could put in their path, but their relatively sudden disappearance during the Paleolithic era indicates that an inability to adapt to some environmental change led to their extinction.

请问为什么这里用一般现在时appear呢？

sayysong

the Neanderthals appear ... , but their disappearance indicates that ...
两个分句时态保持一致

红尘道士

the Neanderthals appear ... , but their disappearance indicates that ...
两个分句时态保持一致

-- by 会员 sayysong (2009/11/19 16:12:18)

这个是og的解释，不过我有个疑问og12-14里面

Sunspots, vortices of gas associated with strong electromagnetic activity, are visible as dark spots on the surface of the Sun but have never been sighted on the Sun’s poles or equator.
(A) are visible as dark spots on the surface of the Sun but have never been sighted on
(B) are visible as dark spots that never have been sighted on the surface of the Sun
(C) appear on the surface of the Sun as dark spots although never sighted at
(D) appear as dark spots on the surface of the Sun, although never having been sighted at
(E) appear as dark spots on the Sun’s surface, which have never been sighted on

答案是A，为什么这里面就不一致了，一致的原则是什么？

rose86511

这个是og的解释，不过我有个疑问og12-14里面

Sunspots, vortices of gas associated with strong electromagnetic activity, are visible as dark spots on the surface of the Sun but have never been sighted on the Sun’s poles or equator.
(A) are visible as dark spots on the surface of the Sun but have never been sighted on
(B) are visible as dark spots that never have been sighted on the surface of the Sun
(C) appear on the surface of the Sun as dark spots although never sighted at
(D) appear as dark spots on the surface of the Sun, although never having been sighted at
(E) appear as dark spots on the Sun’s surface, which have never been sighted on

答案是A，为什么这里面就不一致了，一致的原则是什么？

-- by 会员 红尘道士 (2009/12/26 7:20:26)

你上面说的这道题，but前面说的是：太阳黑子，……，被人们观测到是太阳表面的黑点。这是一个科学事实，我们知道，科学事实是要用一般现在时的。

而but后面讲的是：太阳黑子，……，至今为止（从过去到现在）没有在太阳的两极和赤道被观测到。所以这里要用现在完成时。

这样分析后，其它选项的时态不符合逻辑。

我想，所谓的“一致”是指结构一致，而不是时态一致。