English questions~~~~

[echoinvally]

hi!

 

i don't know if it's appropriate to post some questions about English grammar but i want to have a try

 

i have some questions of English grammars and do hope to get answers from native speakers in a way of "authentic English" 

 

here is a sentence~~~"residents told the BBC that government tanks which had been shelling buildings in the centre of the city withdrew suddenly for reasons that are unclear"

 

i'm kind of puzzled that the time tenses here, in the first part it with a past tense 过去完成时，but it suddenly turned into a present tense in the end.  why? --why they don't keep the tenses in consistency when describe a thing obviously happened in the past and quoted by a local resident's words?

 

my English grammar knowledge is not good, hope i could receive some answers from kind people here  

[liuzhou]

 

residents told the BBC that government tanks which had been shelling buildings in the centre of the city withdrew suddenly for reasons that are unclear"

i'm kind of puzzled that the time tenses here, in the first part it with a past tense 过去完成时，but it suddenly turned into a present tense in the end.

 

 

There are three verb phrases all in past tense, as they refer to events which happened in the past, then "for reasons that are unclear". This is present tense because the reasons are still unclear (in the present).

[Johnny20270]

might make it easier to understand if slightly rephrased ...

 

"for reasons that are, as of yet, unclear". You will hear that phrase used on the BBC.