help, xdf-s4-11, a structure

isuffering

11. Several studies have found that the coronary patients who exercise most actively have half or less than half the chance of dying of a heart attack as those who are sedentary.
(A) have half or less than half the chance of dying of a heart attack as those who are sedentary
(B) have half the chance, or less, of dying of a heart attack than those who are sedentary do
(C) have half the chance that they will die of a heart attack, or less, than those who are sedentary do
(D) are at least fifty percent less likely to die of a heart attack as those who are sedentary
(E) are at least fifty percent less likely than those who are sedentary to die of a heart attack

I know the answer should be E.

But I want to know whether both the following sturctures are ok in Gmat.

sb1 be less likely to do sth than sb2  (Structure1)

sb1 be less likely than sb2 to do sth  (Structure2)

Someone said that Gmat is inclined to use the structure2.

But what about structure1? Definitely ok? Or defnitely wrong?Or it depends?  

Can anybody help?

Thanks in advance.

tongxun

这两个结果表达的意思是不一样的。
A be less likely to do sth than B：有可能A比较可能做B，而不是STH；也有可能是A与B比起来更不容易做STH。
A be less likely than B to do sth ：A与B比起来更不容易做STH。