Onell wrote:The success of the program to eradicate smallpox has stimulated experts to pursue something they had not previously considered possible -- better control, if not eradication, of such infections as measles and yaws.

I guess ,in GMAT, Past perfect should be used relative to other action in SIMPLE PAST..I see no such actions here ...Can someone clarify..Why is past perfect correct here?

hi your understanding of the usage of past perfect is wrong.

Past perfect is used in places where we need to indicate that the action indicated by past perfect occured earlier of the actions presented in past tense

A classic example is

When I came to the railway station, the train had already left.

So here we say that the train has already left is the action which occurred prior to my arrival at the station.

In your example the act of them getting stimulated is in the past but then these guys thought that something was not possible before.

So in this case clearly 'not thinking that something was not possible' occurred earlier than the act of getting stimulated. So the usage of past perfect is the only way you can convey the meaning.

Hope that I made some sense.

phanideepak wrote:

Onell wrote:The success of the program to eradicate smallpox has stimulated experts to pursue something they had not previously considered possible -- better control, if not eradication, of such infections as measles and yaws.

I guess ,in GMAT, Past perfect should be used relative to other action in SIMPLE PAST..I see no such actions here ...Can someone clarify..Why is past perfect correct here?

hi your understanding of the usage of past perfect is wrong.--

Past perfect is used in places where we need to indicate that the action indicated by past perfect occured earlier of the actions presented in past tense

A classic example is

When I came to the railway station, the train had already left.

So here we say that the train has already left is the action which occurred prior to my arrival at the station.

In your example the act of them getting stimulated is in the past but then these guys thought that something was not possible before.

So in this case clearly 'not thinking that something was not possible' occurred earlier than the act of getting stimulated. So the usage of past perfect is the only way you can convey the meaning.

Hope that I made some sense.

Thanks phanideepak,
However , I am not very much clear what makes you think getting stimulated is in the past Do you intend to say its one-time action and thus, is over..

Onell wrote:

phanideepak wrote:

Onell wrote:The success of the program to eradicate smallpox has stimulated experts to pursue something they had not previously considered possible -- better control, if not eradication, of such infections as measles and yaws.

I guess ,in GMAT, Past perfect should be used relative to other action in SIMPLE PAST..I see no such actions here ...Can someone clarify..Why is past perfect correct here?

hi your understanding of the usage of past perfect is wrong.--

Past perfect is used in places where we need to indicate that the action indicated by past perfect occured earlier of the actions presented in past tense

A classic example is

When I came to the railway station, the train had already left.

So here we say that the train has already left is the action which occurred prior to my arrival at the station.

In your example the act of them getting stimulated is in the past but then these guys thought that something was not possible before.

So in this case clearly 'not thinking that something was not possible' occurred earlier than the act of getting stimulated. So the usage of past perfect is the only way you can convey the meaning.

Hope that I made some sense.

Thanks phanideepak,
However , I am not very much clear what makes you think getting stimulated is in the past Do you intend to say its one-time action and thus, is over..

The success of the program to eradicate smallpox has stimulated experts to pursue something they had not previously considered possible -- better control, if not eradication, of such infections as measles and yaws.

in the highlighted part above don't you think the action 'has stimulated' is in the past??

Go semantically don't confuse yourself saying that its present perfect as present perfect is used to indicate about actions in the past and when we have no particular time reference.