时态到底有没有固定用法？大家是不是排除时候最后看时态？

emily727

比如OG12
41. To develop more accurate population forecasts,
demographers have to know a great deal more than
now about the social and economic determinants of
fertility.
(A) have to know a great deal more than now about
the social and economic
(B) have to know a great deal more than they do
now about the social and economical
(C) would have to know a great deal more than they
do now about the social and economical
(D) would have to know a great deal more than they
do now about the social and economic
(E) would have to know a great deal more than now
about the social and economic
to......would do...
50. According to some analysts, the gains in the stock
market reflect growing confidence that the economy
will avoid the recession that many had feared earlier in
the year and instead come in for a “soft landing,”
followed by a gradual increase in business activity.
(A) that the economy will avoid the recession
that many had feared earlier in the year and
instead come
(B) in the economy to avoid the recession, what
many feared earlier in the year, rather to come
(C) in the economy’s ability to avoid the recession,
something earlier in the year many had feared,
and instead to come
(D) in the economy to avoid the recession many
were fearing earlier in the year, and rather
to come
(E) that the economy will avoid the recession that
was feared earlier this year by many, with it instead coming
选A 用had feared
36. 17. GWD25-Q17（原CD16-17）
Until recently, the Inuit people led a nomadic existence, sheltering in igloos, the ice-block domes that are peculiar to north-central Canada, and in structures made of stones, bones, driftwood, and skins.

A.    Until recently, the Inuit people led a nomadic existence, sheltering
B.    During recent times, the Inuit people lead a nomadic existence, sheltering
C.    In the times that are recent, the Inuit people led a nomadic existence, sheltered
D.    Up until recently, the Inuit people, leading a nomadic existence, have sheltered
E.    Until recent times, leading a nomadic existence, the Inuit people were sheltered
A until recently却不用完成时
这是都根据句意理解吗，求教！！

典座

解答一下语法题。刚做完。
recent/recently/recent time，代表着过去，而不是现在。所以要用过去式。Lead的过去式是led。排除B。

CE前半句话都很wordy。不解释。

D中up和until一丝重叠。而且原文说的是until recently，就是很久之前直到最近（过去了），因纽特人是游牧民族，要用过去式。如果要用完成式就应该变为“until now”，说明延续至今。

毛毛carina

第一题是根据句意

第二题是根据动作发生的时候，从过去某个时间开始一直到earlier in the year，所以用过去完成时

第三句也是可以根据意思：直到最近之前， the Inuit people led a nomadic existence。意思是现在已经不是这种生活了，所以是过去式。

在语法方面，until是应该用过去式的~~以下是朗文字典的解释：

if something happens until a particular time, it continues and then stops at that time。

明确说明了某动作是stops at that time~~而不是延续到现在。

~~~~~~~~~~~~~~~~~~~~~~~分割线~~~~~~~~~~~~~~~~~~~~

区别一下：
until recently  直到最近    

recently 不久前到现在

since ***  从过去某个时间点一直到现在