1) I was browsing through my photo albums this morning when I came across some pictures of my first assignment as an intern in a company.
2) When I was browsing through my photo albums this morning, I came across some pictures of my first assignment as an intern in a company.
My questions : What is the difference between the two sentences? Are they interchangeable?
Thank you very much!
Replies sorted oldest to newest
Hello, TWC,
@TCW posted:1) I was browsing through my photo albums this morning when I came across some pictures of my first assignment as an intern in a company.
2) When I was browsing through my photo albums this morning, I came across some pictures of my first assignment as an intern in a company.
My questions : What is the difference between the two sentences? Are they interchangeable?
The main difference between (1) and (2) is that the when-clause only specifies the time of occurrence of the action contained in the main clause in (2), which can also be expressed as follows:
3) I came across some pictures of my first assignment as an intern in a company when I was browsing through my photo albums this morning.
In both (2) and (3), the when-clause answers a when-question:
4) When did you come across some pictures of your first assignment as an intern in a company?
On page 42 of his book "When-Clauses and Temporal Structure," Renaat Declerck calls clauses like the one appearing in (1) "narrative when-clauses":
So-called ‘narrative when-clauses’ do not have the semantic function of
specifying the time of the HC [head clause]-situation or a time to which the time of the HC situation is related: they do not answer the question ‘When?’ Instead, they are semantically like HCs: they ‘push forward the action’ (i.e. when is equivalent to ‘and then’). For this reason they should not be treated as adverbial WCs, but rather as a special type of WC that has many characteristics in common with HCs. The following are some typical examples:
(124)
(a) I was sitting quietly in the kitchen when suddenly a stranger entered the room. (=and then it suddenly happened that…)
(b) She had just dried the last plate and was setting clean coffee cups on a tray, when a dark-haired, spectacled young man put his head through the kitchen window. (LOB)
(c) Closing the garage doors behind her, she was about to turn when she felt the cold muzzle of a gun against her back. (LOB)
(d) I had hardly obtained a pair of spectacles when I ceased to need them, my eyes suddenly getting a second wind. (LOB)
Along these lines, sentence (1) could be paraphrased as follows:
1a) I was browsing through my photo albums this morning and then, in the middle of that process, I came across some pictures of my first assignment as an intern in a company.
In answer to your question as to their interchangeability, I don't think (1) and (2) are exactly the same because there is a difference in the semantic function of the when-clause: while it expresses the time of discovery of some pictures in (2), it expresses a new action in (1).
Thank you very much for your clear and detailed explanation. 
