美国答复OA中的103(a)请问这段话什么意思？

审查员在什么情况下会引用这段话？在答复的时候要注意什么？而且在后面具体权利要求的审查意见中，并看不出来审查员引用在这段话的用意何在？
The factual inquiries set forth in Graham v. John Deere Co., 38. U.S. 1,148 USPQ 459(1966), that are applied for estanblishing a background for determining obiousness under 35 U.S.C. 103(A) are summarized as follows:
1. Determining the scope and cotents of the prior art.
2. Ascertaining the differences between the prior art and the claims at the issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.

103(a)针对创造性，审查员引用Graham案例，是因为这个案例列出了判断创造性的四步法，即审查员说的Determining，Ascertaining，Resolving，Considering

答复时类似我们的三步法，要一步一步的来，

谢谢，明白了。