Learning past tense with Rosetta Stone I'm learning Chinese using Rosetta Stone and i find 99.9% of the stuff that i encounter while learning to be quite logical. In fact this is the first thing in quite a while that doesn't seem to make any sense.

Look at the last two images and their descriptions:

Why does the word 了 follow the verb in the third image, but follows the noun in the fourth image? The situation in both images seems to be the same. And while you're at it, can you explain the word order in the first two images as well?

Thank you
了 functions both as aspectual and modal particle, in the former case it occurs after the verb, in the latter at the end of the sentence. In images 1,3 the completed aspect of the action is referred to, in images 2,4 了 occurs at the end of the sentence to indicate a change（the emergence of a new situation, change in understanding, opinion,ideas, or action, express urging, advice or reminder (quotation from 外国人实用汉语语法)).
In fact in case of #2,4 it could occur twice： 我买了一本词典了，她买了药了 to indicate both aspect and change, but instead of using 了 twice (to indicate both aspect and mood (modal particle use)，it often 
(usually, especially in the case of short sentences ?)
only occurs at the end of the sentence.