Is this placement of 於 wrong or just unidiomatic?
徐良泉於1937年和妻子結婚 


In this sentence, [徐良泉] is the subject. and the rest of the sentence "於1937年和妻子結婚" is in order


  徐良泉和妻子於1937年結婚 


In this sentence [徐良泉和妻子] is the subject, and the rest of the sentence "於1937年結婚" is in order

're-organise sentence into correct sentence order' here seem referring to the correct order of the four sentences, not the word orders in each sentence.


The couple now have children, grand children and great grand children
He married his wife in 1937
The old man was born in Jiangsu
This hundred years old couple have been through a lot of hardship


The correct order of these four sentences is 3, 2, 1, 4

The goal of this exercises is to use your comprehension skill to construct a logically coherent paragraph. All you need to do is to figure out the correct time-line.

None of the sentence is grammatically incorrect

Edit:

Ludi wrote:


  Thank you. The goal is to arrange the words of the sentence, but I had already done that. There is no possibility to choose the order. 


May be they think 和 in "於1937年和妻子結婚" should had been 與. As in "徐良泉於1937年與妻子結婚"(which is a better preposition when 徐良泉 was the subject) 

presuming 和 is incorrect (or not the optimal choice), the only option is to rearrange the sentence into "徐良泉和妻子於1937年結婚" and make "徐良泉和妻子" the subject.

A likely explanation is the author already set the answer as "徐良泉和妻子於1937年結婚" but overlooked the fact that 和(and) can function as 與 (with) too. That meant there could be two correct answers, but the author only allowed one.