求助，大家来帮帮忙

unlike a hurricane ,which can be observed from within ,a tornado is so small that such a study has not been pactical

b, that studying it that way has not been impractical

c for such srudies as this to have been impractical

d,as to not make such a study practical

e,as to be impractical of study

我选的E，答案是A，大家帮忙讲解一下

和so...as to ...在这题里应该是一样吧

是时态的原因吧。

至今为止not pracitcal,应该用现在完成时。

而且e选项的介词of比较奇怪。用to比较对吧。

so...that...如此，以致于（接结果）

so..as to... ？我好象没见过这样是一个＂结构＂呢

搬个凳子，听别人的解释

同意