Demographers forecast

[saurabh2525_gupta]

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

It looks like an if.....then construction. if(develop forecast) then ( need to know more). The if clause is in the present tense, so according to the if.. then rule, then clause should be in the future tense. Here the correct choice is the one that does not obey this rule.

Please help me understand gap in my understanding.

Best Regards,
JOHN

[gunjan1208]

D

Reason 1: Use of would is needed (this zeros on to C and D]
Reason 2: Economic is used (Economical is not right word)

[amit2k9]

economic is the correct choice here.options B and C eliminated.
Among A,D and E.

the forecast models have to be developed.Hence, its in future tense.
A is eliminated.
Between D and E,
after than a subject is required,which is missing in E.
Thus D it is.

[saurabh2525_gupta]

D

Reason 1: Use of would is needed (this zeros on to C and D]
Reason 2: Economic is used (Economical is not right word)

I understand that since it is a conditional sentence, WOULD is required but the entire thing does not fit in the rule.

[gunjan1208]

Hi Saurabh,

What exactly is the issue you have understanding D. I would be able to explain once I know your view.

[saurabh2525_gupta]

Hi Gunjan,

Thank you for replying.

I agree with you on your explanation.

I point where I am stuck is that Verb Tenses can be used to express subjunctive mood with if...then construction. According to that, if(clause in present tense), then (clause should be in future tense)
if(clause in past tense), then ( WOULD + infinitive form)

Here the if clause is in present tense, so then clause should be in future tense. Also it should not use WOULD but the correct answer does so.

Thanks,
JOHN

[gunjan1208]

Saurabh,
Well said. In fact, I thought so. But since you have to choose out of 5 choices, look for the perfect answer not the ideal one.

I chose would because of the following reasoning:
Focus on first two:
(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

I would have gone with these tho choices if they did not have emboldened portion alongwith them.

This portion tells that the task is going to happen in future. Other 3 choices universally have "would". Therefore, though it crossed my mind, I did not bother for logic+rule further.

[saurabh2525_gupta]

Saurabh,
Well said. In fact, I thought so. But since you have to choose out of 5 choices, look for the perfect answer not the ideal one.

I chose would because of the following reasoning:
Focus on first two:
(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

I would have gone with these tho choices if they did not have emboldened portion alongwith them.

This portion tells that the task is going to happen in future. Other 3 choices universally have "would". Therefore, though it crossed my mind, I did not bother for logic+rule further.

You are talking about the portion in red, green or black