The 1950 Graver Tank & Manufacturing Co. v. Linde Air Products Co. Supreme Court decision went a long way
toward establishing the propriety of the doctrine of equivalents, which allows patent law to accommodate reason outside of its exact jurisdiction, and explaining how and when it was to be used.
A. toward establishing the propriety of the doctrine of equivalents, which allows patent law to accommodate reason outside of its exact jurisdiction, and explaining how and when it was
B. toward establishing the propriety of the doctrine of equivalents, which allow patent law to accommodate reason outside of its exact jurisdiction, and to explain how and when it was
C. towards the establishment of the propriety of the doctrine of equivalents, which allows patent law to accommodate reason outside of its exact jurisdiction, and explaining how and when it was
D. toward establishing the propriety of the doctrine of equivalents, which allows patent law to accommodate reason outside of its exact jurisdiction, and explained how and when they were
E. towards establishing the propriety of the doctrine of equivalents, allowing patent law to accommodate reason outside of its exact jurisdiction, and explaining how and when they were[/quote]
Answer:
This question can actually be solved without getting into the mess of toward vs towards, though they seem as easy elimination but not error proof.
So the question is basically saying,
The 1950 Supreme Court decision went a long way TOWARD/TOWARDS (lets keep both for now)
a. establishing the propriety of the doctrine of equivalents
and
b. explaining how and when it was to be used
notice that 'which allows patent law to accommodate reason outside of its exact jurisdiction' is modifying the doctrine (of equivalent in prepositional phrase, so which can reach back) and also it is enclosed within double commas which here serve as the start and end of the modifier. Also, 'how and when it (read it as doctrine) was to be used' is explained by Supreme court decision and not by doctrine itself.
So clearly point a and point b above,are the two consequences of supreme court action, hence they both should be parallel.
Choice A): seems alright, clearly 'it' in 'explaining how and when it was' refers to doctrine
Choice B): establishing and to explain are not parallel, definitely wrong.
Choice C): establishment and explaining are not parallel, again wrong.
Choice D): here the major problem is they (as verb-ing and verb-ed can be parallel), clearly they cant refere to doctrine as its singular, again wrong answer
Choice E): Again a they, wrong answer.
So clearly our right answer is A.
Hit Kudos, if you like the explanation.