Place of 了 particle for the past tense? Ok, I saw explanation that:


我去了商店。（means: I have gone to the shop already）
我去商店了。（means: I am going to the shop now）


So I expected to meet 了 for the past tense only right after the verb:


  昨天我去了商店。


But actually I saw that this is also possible:


  昨天我去商店了。/ 昨天我们去长城了。


So is it correct for the past tense to separate 了 with the verb? Is there any difference in meaning?
Both are correct for past tense. They have the same meaning, with subtle difference on the point of emphasis.

"我去了商店" lays emphasis on the action "went to the shop", while "我去商店了" lays emphasis on the destination of the action, i.e. "the shop".

So it'll be more natural to use "我去了商店" as the answer to the question asking "what did you do" (你做什么去了), and use "我去商店了" as the answer to the question asking "where did you go" (你去哪儿了). (Note that they are just more targeted and straightforward to the answer, using another one as the answer is fine too.)